Other CRT chassis & equivalence table¶

The arcade chassis landscape is vast. This page gathers the other makers (Toei, Neotec, Rodotron/Pentranic, universal Wei-Ya…) and above all the equivalence table: which chassis can replace a dead one. Repair is always the same family of steps → CRT safety + Recap.

Makers & common chassis¶

Maker	Chassis (e.g.)	Region / use
Toei	TC-RM251S (25"), CM-F20U, CM-14, ⓘ GMM-8	JP — a major, alongside Nanao/Sanwa; the GMM-8 (connection diagram C-151-2, August 1975) was fitted to 1975-76 Taito games → Taito 1975-1977 drawings
Neotec	NT-2700 series / NT-2702 (≈ Nanao MS8/MS9)	replacement chassis
Rodotron / Pentranic	CH-688A, Rodotron 666a / 666b1	replacement chassis (EU/AU)
Wei-Ya (universal)	C825H-2 / C825HR-2 / 825H1, 2929 / 2931a	universal replacement chassis (modern tri-sync)
Makvision / Kortek	M3129, 3125B…	modern tri-sync → dedicated page
Electrohome	G07 (19″ R.G.B. colour)	US/CA — manufacturer manual (54-7294-01, May 1980) and the Bally Midway bulletin; see the box below
Electrohome	G05 (monochrome X-Y, Quadrascan)	US/CA — a vector monitor, manufacturer manual archived below
Wells-Gardner	Quadrascan Color X-Y (Atari ref. 92-053)	the colour counterpart of the G05 — see also its own page
Motorola	chassis 19VP111 / 23VP111, models XM501-10 / XM701-10	US — 110 W nominal, mains 120/240 V switch selected
Matsushita	19″ Color Raster Display (Atari manual TM-220)	JP — 19″ raster, full schematic and parts list
Sharp	XM-2001N (19″ colour raster)	JP — supplied to Atari, manual TM-304 © 1987; see the box below
Sanyo	EZV 19″ (19″ colour raster)	JP — supplied to Atari, manual TM-311 © 1987; see also the Sanyo 20-EZ
Amplifone	13″ Color X-Y (Atari A200003)	US — ⓘ a COLOUR vector set, built "to Atari specifications" → Atari vector games
Zenith	CD19MXRF06 (19″ colour)	US — fitted by Bally Midway alongside Wells-Gardner and Electrohome; see the box below
Others seen	Orion, Glendale, Philips, Hitachi, Vision Pro, Betson…	per cabinet/region

Wells-Gardner, Electrohome, Zenith — what a game manual says about all three at once ✅

Monitor manuals describe one chassis. The monitor chapter of Bally/Midway's MCR II System Games — Standardized General Instructions (© 1983) does something else: it describes the three makes Bally Midway fitted, in the same text, saying where they differ. That is a view none of the three makers could publish.

ⓘ Zenith was named nowhere on this wiki before this document.

	Wells-Gardner	Electrohome	Zenith
Models named	K4806 (13″), K4906, K4956 (19″)	G07-902 (13″), G07-904 (19″)	CD19MXRF06 (19″)
Sync IC	HA11423	HA11244 (in IC501)	221-175 (Zenith part number)
Colour drive controls	two: red, green	two: red, green	⚠️ three: red, blue, green
Cutoff controls	in the emitter of the colour output transistors	same	in the interface section
A.C. picture signal	to the base of the output transistors	through the emitters	through the emitters

⚠️ "These ARE NOT interchangeable!" — the sentence is the manual's, and it is about the three sync ICs. Same function, same circuit idea, three non-substitutable packages.

ⓘ The rest is common to all three: composite negative sync, vertical at 60 Hz, horizontal at ≈ 15,750 Hz, and an EHT quoted at ≈ 24,000 V — "THIS AREA HAS ABOUT 24,000 VOLTS ON IT AND IT CAN KILL YOU!" → CRT safety.

ⓘ The manual also gives a rule for swapping parts between makes, and it is a simple one: "compare the manufacturer's part number between each one. If they match up, they are the same part."

"Monitor Manufacturers" — the same page, twice, and it does not say the same thing ✅

Both Bally/Midway service-bulletin compilations archived on this wiki carry a page headed MONITOR MANUFACTURERS — ⓘ the list of display suppliers an operator was meant to call.

	Service Bulletin vol. 2 (p. 86)	Service Notes vol. 1 (p. 90)
Range covered by the compilation	up to Gorf / Rally-X (1980-81)	up to Tron / Ms. Pac-Man (1982)
Motorola Inc., Display Products, 455 East North Avenue, Carol Stream, Illinois 60187 · (312) 231-4400	✅	✅
Wells Gardner Electronics Corp., 2701 North Kildare Avenue, Chicago, Illinois 60639 · (312) 252-8220	✅	✅
Electrohome Limited, 809 Wellington St. N., Kitchener, Ont. N2G 4J6 · (519) 744-7111	✅	✅
Named service contact at Wells Gardner	⚠️ one name	⚠️ a different name

ⓘ All three addresses and all three phone numbers are identical from one volume to the other; only the Wells Gardner contact changed. ⓘ (The three people named appear in the archived documents; this wiki does not relist them.)

⚠️ And it is the comparison with 1983 that speaks. The monitor chapter of the MCR II System Games (© 1983, above) describes Wells-Gardner, Electrohome and Zenith. ⓘ Motorola is gone from it, and Zenith was in neither 1980-82 list. One game maker's supplier base therefore turned over in two or three years — which is why a Bally/Midway cabinet of that era can have left the factory with either.

ⓘ Electrohome Limited, 809 Wellington St. N., Kitchener, Ontario: the same address as the manufacturer's G02 manual archived below, which gives only the city.

19″ tubes: they all fit, and that is the trap ✅

The same manual publishes a picture tube interchangeability chart. It separates two cases that do not fail the same way.

13″ — the wrong tube will not fit. "The pins on the neck of the CRT will not fit in the socket should you use the wrong CRT."

13″ monitor	Tube
ELECTROHOME G07-902	370ESB22
WELLS GARDNER K4806	370KSB22

⚠️ 19″ — the wrong tube fits. "All of the picture tubes will fit no matter which is used. But if you use the wrong one, you will have problems with purity and/or dynamic convergence." The manual describes both symptoms: bad purity shows blotches of other colours instead of a solid field when you turn a colour up; bad dynamic convergence shows colour fringing around solid lines at the edges of the screen.

19″ monitor	Tubes declared correct
ELECTROHOME G07-904 ("ALL")	19VMNP22 RCA · 19VMJP22 RAULAND · 510UJB22 HITACHI
WELLS GARDNER K4906	19VLTP22 RCA · 19VMLP22 ZENITH · 19VMKP22 PHILLIPS
ZENITH CD19MXRF06	19VMLP22 ZENITH · 19VLTP22 RCA · 19VMKP22 PHILLIPS

ⓘ Wells-Gardner and Zenith accept the same three tubes, in a different order of preference. Electrohome shares none with the other two. ⓘ PHILLIPS is the manual's spelling; the maker is Philips.

⚠️ And the manual warns about itself: "The factory recommended CRT type could change in the future for one reason or another […] you can call another picture tube company to see if they have a replacement number to recommend… but caveat emptor — let the buyer beware." ⓘ These references date from 1983; this wiki reproduces them as the state of a catalogue on a date, not as compatibility guaranteed today.

ⓘ A complement, not a contradiction: the manufacturer's G07 manual archived below covers the G07-904 and G07-907 — the 13″ G07-902 is not in it. It is Bally Midway that names it.

Electrohome G07 — what the manufacturer's manual adds to the bulletin

The Service and Operation Manual (54-7294-01) archived below covers models G07-904 and G07-907. ⚠️ It carries two dates: "this information is up to date as of MAY 1980" at the head, and "this information is correct as of June 1980" on the G07-907 Service Data Reference page. Both are in the document; this wiki does not choose. It gives what the Bally Midway bulletin could not: the nominal values.

Item	What the manual writes
Supply	108 to 132 V AC, 44 to 63 Hz
High voltage (EHT), 19″ models	22.5 to 25.5 kV, measured at I(beam) = 0 and B1 = 120 V
B1	⚠️ to be set to 120 V DC with R909

⚠️ That is the value missing yesterday. The Bally Midway bulletin addresses the case "B+ at 138.5 V or more" without ever saying what B+ should be. The manual says it: 120 V. The two documents complete each other — one gives the setting, the other the fault.

Input pinout, connector J201:

Pin	Signal	Impedance	Range
1 · 2 · 3	Red · Green · Blue	5 kΩ nominal	0 to 4 V
4	Ground	—	—
5	Vertical sync	35 kΩ nominal	+2 to +4 V
6	Horizontal sync	35 kΩ nominal	+2 to +4 V

For negative pulses, the manual points to J202 — D2 for vertical, D3 for horizontal.

The adjustments, by their designator: vertical linearity R406 · vertical hold R422 · horizontal frequency R504 · vertical height R408 · vertical and horizontal centering by 3-position tabs · CRT cut-off R114 (red), R115 (green), R113 (blue) · video drive R105 (red), R106 (green) · width coil L503 · focus R11.

The manufacturer's four warnings, reproduced

Power-up: outside the cabinet, "an isolation transformer must be used for the AC power source" — and the manual specifies 1 A capability;
X-radiation: "it is IMPERATIVE that the EHT circuitry IS NOT modified";
High voltage: "capable of delivering LETHAL quantities of energy. To avoid DANGER TO LIFE, do not attempt to service the chassis until all precautions […] have been observed";
CRT handling: the tube holds a high vacuum and can implode. "Shatter-proof goggles must be worn", and never handle it by the neck.

Electrohome G07 — what the Bally Midway bulletin documents, and nothing more

The Service Bulletin of 21 October 1982 archived on this page covers the G07's HVL circuit. The values below are taken from it as they stand — this wiki publishes no others for this chassis.

Marking	What the bulletin says about it
B+	138.5 V DC or more = the case the procedure addresses
X701	the transistor whose collector is disconnected at the start, and which must be reconnected at the end — the bulletin says so explicitly
X04	the regulator's output transistor; B+ is measured at its emitter
X04, X901, X902, D905, C905	the regulator circuit, to check if B+ stays high with a raster
IC501, X501, T-501, X01, T-502	the horizontal chain, to work back up from the oscillator when there is no raster

The procedure's logic: raster present and B+ normal once X701 is disconnected → the fault is in the protection circuit. B+ still high → the fault is in the regulator. No raster at all → it is the horizontal chain.

⚠️ High voltage. This chassis is worked on with the tube discharged → CRT safety.

Motorola 19VP111 / 23VP111 (XM501-10, XM701-10) — the manual that gives a number

The Motorola service manual, file VP12 (ref. 68P65130A70-1, 3-75, © 1974, Display Products, Carol Stream, Illinois — cover price 80 cents) covers two chassis "identical except for the CRT size" and presents itself from the first line as built for the video game market.

Item	What the manual writes
Power rating	110 watts nominal · 50 watts without the 5 volt supply
Mains	120/240 V AC, 50/60 Hz, ⚠️ *switch selected* (SW1) — no auto-ranging
Video input	0.5 to 2.5 volts composite peak-to-peak, ⚠️ sync negative
Audio output	5 watts peak — this monitor carries its own amplifier
Tube	114 degree deflection, with implosion protection
Auxiliary output	⚠️ a 5 volt / 3 amp supply "to power external logic systems"

ⓘ The regulator holds the output constant for ±15 % input variation; the main rail is the +73 V. ⚠️ The specification table prints 120/240 V and the theory of operation 115/230 V, for the same SW1 switch. Both are reproduced; this wiki does not choose.

A numeric safety criterion — and it is void if you keep the isolation transformer

Motorola describes a leakage current test with an acceptance value:

A 1000 ohm per volt AC voltmeter, shunted with a 1500 ohm, 10 watt resistor; one probe on "any portion of the unit exposed to the operator such as the cabinet trim, hardware, controls, knobs", the other on a true earth, of the "cold water pipe" kind. ⚠️ The voltage read may not exceed 7½ volts. Above that, "a potentially dangerous leakage path exists". The test is to be repeated with the power plug reversed, where applicable.

⚠️ And here is the sentence you do not expect: "BEFORE RETURNING A SERVICED UNIT […] DO NOT USE A LINE ISOLATION TRANSFORMER WHEN MAKING THIS TEST." The transformer that protects you while servicing breaks precisely the earth reference this test measures. It protects the workshop; it hides the fault. The two instructions do not contradict each other: they do not apply at the same moment. → CRT safety

⚠️ And the rule that goes with it: "NEVER RETURN A MONITOR which does not pass the safety test until the fault has been located and corrected."

Two handling details the other manuals do not give

The direction of the discharge. Motorola does not merely say discharge the tube, it says how: short the anode to chassis ground — "not cabinet or other mounting parts" — and "when discharging, go from ground to anode", or use a well insulated piece of wire. ⚠️ The wire starts at ground and goes to the anode, not the other way round.

The pressure, as a number. "rough handling may cause it to implode due to atmospheric pressure (14.7 lbs. per sq. in)" — about 1 bar over the whole area of the faceplate. And for handling: safety goggles and heavy gloves, both.

The manual adds two instructions this wiki had not written down: put the protective devices back — "fishpaper, insulation resistors and capacitors and shields" — after working on the unit; and if the high voltage is adjustable, set it to the manufacturer's value, because above it "exposure to unnecessary X-ray radiation could result".

VP12 — what the theory of operation lets you diagnose

This is one of the few manuals on this wiki to explain what each stage does, which yields identifiable faults rather than a parts list:

No sound at all, on early models → diode D22 "polarizes the speaker insuring proper installation. If it is installed wrong, little or no audio will be developed." ⚠️ A speaker wired backwards, not a dead amplifier.
The speaker is protected by a lamp. "Lamp E1 serves to protect the speaker if the audio output transistor fails, it also protects the transistor should the speaker leads be shorted." ⚠️ A blown lamp in that position is not a dead indicator: it is a fuse that did its job, and there is a cause to find.
The white spot at switch-off is handled by a dedicated circuit: the spot killer Q21, normally not conducting, with C51 charged to the supply voltage. At switch-off C51 discharges through R96, turning Q21 on, which removes the positive potential from the brightness control and connects the CRT cathode to ground — the tube conducts hard and discharges the high voltage. ⚠️ A lingering white spot at switch-off therefore points at this circuit; and it is also what empties the EHT at shutdown — its absence or failure changes what is left in the tube when you open it.
Adjustments: horizontal hold R34 (range set by the core of L1), vertical hold, brightness and volume on the rear panel; contrast, vertical and width on the circuit panel, reachable from the rear. Video bias R10. Width: series coil L4; linearity: magnetically biased coil L3.
Power supply: series pass Q16, reference amplifier Q15, output driver Q14; temperature compensated zener D6; the R71 / R74 / R73 divider with the arm of R74 as the reference input to the base of Q15. The external 5 V works like the 73 V, minus the reference amplifier — that one is inside the IC.
Frequencies: vertical oscillator 50-60 Hz, horizontal oscillator 15,000-16,000 Hz.

Removing the board — the service note, as written

"To prevent damage to the board or foil when removing the circuit panel it may be necessary to pry up slowly, IN STAGES around the edges […]. Start at one corner and move all around the board keeping the screw driver tip against the chassis. When installing, apply pressure at the edges near the pins. Do not force down on the components."

G05 \"Quadrascan\" monochrome — ⚠️ powering down in the wrong order burns the tube, permanently

The Instruction and Service Manual for the G05 Monochrome X-Y Monitor (Electrohome TM-146, ref. 54-7279-01 Issue 2, "up to date as of October 1979") opens its warnings with a power-down sequence, ahead of X-radiation and high voltage:

1. POWER DOWN WARNING — "REMOVE INPUT SIGNALS TO DEFLECTION AMPLIFIER BOARD (P-703) […] BEFORE REMOVING POWER TO REGULATOR BOARD (P-100)"

and elsewhere it says why, bluntly: "This sequence must be followed or a phosphor burn may result. This damage is permanent and cannot be repaired."

⚠️ On a vector display, cutting the power while the signal is still coming in leaves the beam parked on one spot of phosphor while the voltages collapse. The tube keeps the mark. It is the opposite of the raster reflex — where you kill the mains without a thought — and it is a bench manoeuvre, not a fault: you catch it while working.

G05 — two checkable criteria, and an indicator that talks

Brightness has a limit, and it is visible. The manual warns that the control "has more than 100 % brightness range on most tubes", and gives the marker: keep it below the point where a centre spot appears on the CRT with no input signal. Beyond that, "may result in a phosphor burn".

An indicator tells you when the spot killer has bitten. "A spot killer circuit is used to blank the CRT under a no signal condition. When the spot killer is active, the CRT will be extinguished and LED D507 will light." ⚠️ Black screen + D507 lit = the monitor is working and is not receiving a signal. That is not the same fault as a black screen with D507 dark.

⚠️ The high voltage is to be checked periodically, against a stated value: "Periodically check the high voltage for proper value (14 KV at 0 beam current) using a meter of known accuracy and calibration". And its adjustment is a factory one — reachable through a hole in the cover, ⚠️ "use insulated tool to adjust".

G05 — supply, pinouts and what is adjustable, as printed

⚠️ Like the colour Quadrascan, this monitor does not take mains. "A.C. power must be applied to the monitor through plug P100 from the isolated secondary winding of a power transformer", at line frequencies from 47 to 63 Hz. And ⚠️ two models carry the same connector for different voltages:

Model	Main winding	Filament
G05-801 — "25 volt operation"	28-0-28 VAC RMS ± 15 %, capable of 0 to 2 A DC	6.3 VAC ± 10 % at 0.45 A nominal
G05-802 — "35 volt operation"	37-0-37 VAC RMS ± 15 %, capable of 0 to 2 A DC	6.3 VAC ± 10 % at 0.45 A nominal

P100 pinout (identical in both models, voltage aside): 1 and 4 = the main winding · 2 and 5 = ground, the centre tap of that winding · 3 = filament ground · 6 = filament 6.3 VAC.

P703 signal pinout:

Pin	Signal	Impedance	Voltage
1	X	1 kΩ	± 10 V, 0 V centre
3	Y	1 kΩ	± 7.5 V, 0 V centre
5	Z	220 Ω minimum	0.5 V blanking · 1.0 V off · 4.0 V full on
2 · 4 · 7	grounds	—	—
6	key	—	—

EHT: 14 kV at zero beam current.

⚠️ What is adjustable and what is not — the manual is categorical, and prints it on its figures too: "ONLY the brightness control (R519) and the contrast control (R526) on the deflection amplifier PCB are 'field adjustable'. ALL other controls, including X and Y linearity, focus, and high voltage, have been factory adjusted and should not be tampered with." And on the regulator board: "there are no field adjustable controls on this PCB".

For the record, the factory controls and where they sit: HV adjust and focus in the EHT supply module (access through a hole in the cover for one, in the heat-sink wrap for the other); linearity R731 / R736 for X and R631 / R636 for Y, on the deflection amplifier board.

Matsushita 19″ (Atari TM-220) — ⚠️ two supply types, and the manual does not say which you have

The Service Manual for the Matsushita 19-Inch Color Raster Display (Atari TM-220, 1st printing, © 1982 Atari; built "to Atari specifications" by Matsushita Electric Industrial Co., Ltd., Television Products Department, Osaka) opens its data sheet on an alternative:

Line Voltage — "120 VAC, within +10 % and −15 %; or 145 VDC, within ± 5 % (Atari, Inc. will specify the type of input voltage at the time of purchase.)"

⚠️ So the same manual covers a monitor that takes DC and a monitor that takes AC — and nothing in the manual tells you which one is in front of you. It was specified at the order. Establishing that is part of the job, not a preliminary.

ⓘ And the manual warns separately: "If you service [it] on a test bench, use an isolation transformer or the power supply that came with the game […]. Do not use line voltage or a power supply from a black-and-white game, because the voltages produced by those sources will damage this display." ⚠️ This wiki does not join the two sentences on the manufacturer's behalf — the manual allows the isolation transformer in the line before — but the 120 V / 145 V DC alternative is reason enough to know before you plug anything in.

⚠️ Third monitor on this wiki that a black-and-white game's supply destroys, after the colour Quadrascan and alongside the monochrome G05 above: on the vector sets it was 25-0-25 or 28-0-28; here it is an input type to verify. The general rule is the same: never power an arcade monitor from whatever is to hand.

The discharge, with numbers: a 20 kV jumper, and two minutes' wait

This is the only manual on this wiki that specifies the tool and the delay:

"When discharging the anode, go from ground to the anode connection with a well-insulated 20-kV jumper. Allow two minutes to pass and discharge the anode again."

✅ The two minutes are new here. The CRT safety page already said to repeat the discharge because the charge builds back; it did not say how long to wait. Two minutes, then again.

✅ And an insulated 20 kV jumper is a tool, not a screwdriver. ⚠️ That does not close the open question on the method page, though: a jumper is still a hard-contact discharge, not a resistive one, and the G05 above's objection about semiconductors still stands.

ⓘ A detail the other manuals settle less well. Where the others write "never by the neck", Matsushita specifies: "Never lift the CRT only by the neck; the neck should only be used to guide the lifting process." The neck guides; it does not carry.

Matsushita 19″ — voltages, pinout and tolerances, as printed

Currents and voltages

Item	Value
CRT anode current (average)	< 700 µA
High voltage	+26.5 kV ± 1.5 kV
B+1	+180 V, within ± 1.0 V
B+2	⚠️ +123 V, within ± 0.5 V — adjustable
B+3	+20 V, within ± 2.0 V
B+4	+12 V, within ± 1.0 V
CRT heater	± 6.4 V, within ± 0.2 VAC (RMS)

ⓘ The video B+ is set by R812, at test point D91; the horizontal oscillator disable circuit is tested at R802.

Tube and scan rates — CRT #510TFB22AW, 19 inch, 90° · horizontal 15.750 kHz ± 400 Hz · vertical 60 Hz ± 5 Hz · consumption 150 W max. · line frequency 47 to 63 Hz.

Mechanical and convergence tolerances — maximum misconvergence 0.25 mm (0.4 mm total) at centre, 0.5 mm (0.7 mm total) at the edges; yoke tilt: the declination of a horizontal line stays within 0.10 inch (2.54 mm) of the CRT centre markers. Purity: "practically uniform throughout the screen area after degaussing with a hand-held degaussing coil".

⚠️ A conversion error in the source, reproduced and flagged. The data sheet prints "0° to +55 °C (+32° to +151 °F)". 55 °C is 131 °F, not 151 °F — and the sister manual for the colour Quadrascan, from the same publisher, does print "0 to 55° C (32 to 131° F)" for the same range. This wiki reproduces what is written and flags it; it does not silently correct a source. Humidity: 10 to 90 %, non-condensing.

Pinouts — ⚠️ yet another colour order:

Pin	6-pin video connector
1	not used
2	sync — composite, negative
3	ground
4 · 5 · 6	⚠️ Blue · Green · Red

2-pin power connector: both pins at 120 VAC.

⚠️ Three manuals, three colour orders: G07 1 R / 2 G / 3 B · Sejoo "Vision" 1 B / 2 G / 3 R · Matsushita 4 B / 5 G / 6 R. A pinout never transposes from one chassis to another.

Input levels — RGB at test points N1, N2, N3 on the video amplifier PCB, 0.5 to 4.0 V peak-to-peak; composite sync at D33 on the main PCB, 1 to 5 V peak-to-peak, negative polarity, pulse width 3 to 5 µs horizontally and over 190.5 µs vertically.

⚠️ One test is mandated before the monitor goes back into the cabinet — beyond the usual checks (no pinched harnesses, fishpaper, covers and shields refitted): "Perform the Horizontal Oscillator Disable Circuit Test given in Chapter 7." It is an X-ray safeguard: the manual indeed lists X-radiation among the three dangers "if the display is out of adjustment".

Atari The Book (1980) — the only document that gives one symptom across four makes at once

The Book — A Guide to Electronic Game Operation and Servicing (Atari TM-129, © 1980, Coin-Op Field Service, ~180 pp. in a three-ring binder, $39 for a spare copy at the time) is the Atari repairer's training manual. Its chapter 3 is about monitors, and it does what no manufacturer's manual can: it puts the makes in columns.

ⓘ The document owns its tone — the introduction lists what the book will not do: "Make you a technician · Turn you into an engineer · Fix all your game problems · Repair printed-circuit boards, or · Make coffee."

The vocabulary first, because the table uses it:

Term	What you see on screen
Vertical roll	an unstable picture moving up or down, "somewhat like a filmstrip"
Horizontal tear	a picture diagonally torn in several places
Horizontal collapse	a narrow vertical raster line, top to bottom of the screen
Vertical collapse	a narrow horizontal line, left to right — "caused by no vertical motion"
Retrace lines	four to eight thin white lines running diagonally

✅ And the method that goes with it: "When two symptoms appear at the same time on the screen, you can use the tables to pinpoint the circuit." Two crossed symptoms beat one symptom alone.

Figure 4 — the same fault, four makes: the first two sections, as printed

⚠️ The Motorola XM501/701 column is exactly the chassis whose manufacturer's manual is absorbed higher up this page. For that one monitor, this wiki now holds the maker's document and the customer's troubleshooting sheet — written by two different houses.

"Horizontal Tear" — a picture torn diagonally

Circuit and cause	Motorola XM501/701	Motorola XM5000/7000	TEC Videoelectronics	Wells-Gardner
A. Sync separator — separator transistor	Q5	Q10	Q301	Q206
amplifier transistor	Q1	Q11	Q400	Q201
shorted diode	D23	—	D201	—
phase diodes open or shorted	D7	D5, 6	D401, 402	D205
shorted capacitors	C2	—	—	C201
B. Feedback separator — capacitors open or shorted	C15, 32	C12, 14	C402, 415	C207, 210
resistor open	R45	R24	R408	R216

"Black Screen — Fuse Blown"

Circuit and cause (horizontal output stage)	Motorola XM501/701	Motorola XM5000/7000	TEC Videoelectronics	Wells-Gardner
output transistor shorted	Q9	Q9	Q403	Q103
damper diode shorted	D1	D7	D403	D106
limiter diode shorted	D2	D8	D801	D206
high-voltage diode defective	D4	D11	D404	D105
high-voltage transformer defective	T2	T2	T403	T102

ⓘ Figure 4 runs on for several pages — Black Screen · Fuse OK, Low Voltage Power Supply Too Low and Too High, No Video or Distorted Video, Raster OK, No Raster — Video Visible, Horizontal Collapse, Vertical Collapse — in the same four-column format. The two sections reproduced here are the most common; the rest are in the archived document, and were not copied out, not having been read line by line with the same care.

Quadrascan X-Y: three measurements for 90 % of the faults, and a quadrant table

The Book reduces the Atari vector display to three boards: the power supply at the bottom of the frame, which provides the ± 25 V; the high-voltage board inside the cage on the left panel, which produces the tube's high voltages and the 90 V for the Z amplifier; and the amplifier board, carrying all three amplifiers — X to the X yoke windings, Y to the Y yoke, and Z for blanking and brightness.

✅ "Ninety percent of the problems in an X-Y monitor can be diagnosed with three key voltage measurements."

+ 25 V — on the case of the +X driver transistor (type 2N3716);
− 25 V — on the case of the −X driver transistor (type 2N3792). ⚠️ "If one or both of these voltages are too low or high, proceed to the power-supply section."
+ 90 V — on the tab (or the nut holding it down) of the Z amplifier transistor Q504, right above the brightness control. ⚠️ "If the voltage is lower or higher than 90 V, proceed to the high-voltage board section."

✅ And if all three are right: "proceed to the XYZ amplifier board". The manual insists: "Remember, always make these three measurements first!"

ⓘ Finding the power transistors at the top of the amplifier board, on the large heat sink: the upper one closest to the picture tube is the −Y driver (2N3792), the one below it (2N3716) is the +Y; the two closest to you are the X drivers — top is −X, bottom is +X.

Figure 6 — reading the fault from the shape of the picture (vector)

On an X-Y display, the part of the screen that is missing names the failed amplifier. The manual gives four examples, and leaves the last one to the reader:

Symptom on screen	Present	Missing	Probable cause
A — a thin line	+Y, −Y	+X, −X	X amplifier
B — one-half picture	+X, −X, −Y	+Y	Y amplifier
C — one-quarter picture	+Y, +X	−X, −Y	X or Y amplifier, or the −25 V supply
D — one-quarter picture (other quadrant)	—	—	ⓘ "You figure out this one" — the exercise is in the manual, the answer is not

ⓘ The reasoning rests on figure 5 of the same chapter, which cuts the screen into four quadrants by the sign of X and Y: "To determine where the problem lies, first determine what is present and then what is missing."

TEC Videoelectronics TM-600 / TM-623 — Atari's fourth column, checked at source ✅

The TM-600 and TM-623 Service Manual (TEC Videoelectronics Inc., 3010 Scott Boulevard, Santa Clara, California) fills a precise gap: ⓘ TEC is one of the four columns in Atari's cross-reference table reproduced higher up this page — and this wiki quoted its designators without holding a single TEC document.

ⓘ It is the monitor chapter of a game manual: the pagination runs 103 to 105 and the footer reads FIRE TRUCK™. It is the Atari manual for the game that carried this chassis.

✅ All nine designators The Book attributes to TEC are in the manufacturer's own parts list, with the same function:

Designator	The Book (Atari, 1980)	TEC parts list
Q301	separator transistor	Sync Separator ✅
Q400	amplifier transistor	ⓘ Phase Inv — same part, other name
D401 · D402	phase diodes	Phase Det ✅
Q403	horizontal output transistor	Horiz Output ✅
D403	damper diode	Damper ✅
D404	high-voltage diode	H.V. Rectifier ✅
T403	high-voltage transformer	F.B.T. ✅
D801	limiter diode	ⓘ 400V Rectifier — same part, other name

⚠️ Two divergences, and they are of vocabulary, not of fact: Atari calls "amplifier" what TEC calls a phase inverter, and "limiter" what TEC calls a 400 V rectifier. Both documents name the same part in the same place. ✅ A 1980 troubleshooting table written by the customer, set against the maker's own parts list forty-five years later: nothing to correct.

Data sheet, as printed

Item	Value
Tubes	19″ (500 mm) for the TM-600 · 23″ (584.2 mm) for the TM-623 — 114° both, integral implosion protection
Mains	115 V or 230 V, 50-60 Hz, ± 10 %
Consumption	60 W
Video input	"0.5 volts composite P/P for 100 volts" · 2.5 V P/P maximum · ⚠️ sync negative at input
High voltage	18 kV nominal at 0 µA beam current
Horizontal retrace	12 µs maximum
Resolution	500 lines minimum at picture centre
Scanning	⚠️ horizontal "15.750 Hz ± 500 Hz" (sic) · vertical 50-60 Hz
Tone burst amplifier	5 W peak on TTL drive at nominal line, fully adjustable · 4 W peak at low line
Environment	operation 50 °C max (122 °F) · storage −40 to +65 °C

⚠️ The "15.750 Hz" is printed as such: it is a misprint for 15.750 kHz, the standard line frequency — which the manual itself confirms elsewhere by giving a 12 µs horizontal retrace, impossible anywhere near 15,750 Hz. ⓘ The word "Scaning" is also misspelled in the original. This wiki reproduces and flags; it does not correct a source.

ⓘ What is inside, as the maker enumerates it: a picture tube, one integrated circuit, 20 silicon transistors, 18 silicon diodes, 2 germanium diodes and one high-voltage selenium diode. With a 5 V / 3 A supply dedicated to the TTL control board, and a double-pulse-type AFC circuit "to obtain a stable picture".

Fuses, on the rear: F902 2 A · F903 0.5 A · F904 5 A, beside the line switch and the P1 connector. ⓘ The TM-623 nameplate reads "AC 115 V / 230 V, 50-60 Hz".

ⓘ A few useful designators from the parts list: Q904 5 V regulator (MJ2955) · Q901 power regulator · Q902 regulator amp · Q903 reference amp (LM1796) · Q200/Q201/Q202 the three video stages · Q302/Q303 vertical oscillator and amp · Q304/Q305 vertical output · Q401 horizontal oscillator · Q402 horizontal amp · T401 horizontal oscillator · T402 horizontal drive · T901 power transformer · V801 the tube (500SB4).

Electrohome G02 — 31 kV, and confirmation of a publishing detail

⚠️ Its high voltage is the highest on this entire wiki: "CAUTION: This chassis employs a high EHT (31 KV) pix tube." — against the 14.5 kV of the WG 19V2000, the TEC's 18 kV, the Sejoo's 25 kV. ⓘ And the manual ties that value explicitly to the radiation risk: the only protection it names against soft X-rays is "ensuring the EHT value is correctly set".

✅ It confirms an observation made yesterday about the G07 — which I had taken for an anomaly. The G02 also carries two dates: "this information is up to date as of MARCH 1978" at the head, and "this information is correct as of May 1978" on the Service Data Reference page. ⓘ So it is not a quirk of the G07: it is Electrohome's publishing convention. One date for the body of the manual, another for the service reference sheet.

ⓘ And the same anti-arc wording as the G05, word for word: "In order to prevent damage to solid state devices, do not arc pix tube anode lead to chassis or earth ground." ⚠️ Three Electrohome chassis, the same prohibition — it is a house position, and the CRT safety page treats it as one.

ⓘ Ventilation: maximum ambient temperature 66 °C, with the instruction to keep the underside of the chassis clear of anything hindering airflow to the power-dissipating components. Four mechanical configurations are documented — 19″ and 25″, standard and "custom".

Two makes, one specification — the Atari envelope ✅

Atari published, under its own TM numbering, the service manuals of monitors it bought elsewhere. Two of them are archived here, both © 1987, Atari Games Corporation, 675 Sycamore Drive, Milpitas:

	Sharp XM-2001N	Sanyo EZV 19″
Reference	TM-304, 1st printing, 23 pp.	TM-311, 1st printing
Title	19-Inch Color Raster Video Display	19-Inch Color Raster Video Display
Mains	100 VAC, +10 % / −15 %	identical
Line frequency	47 to 63 Hz	identical
Consumption	74 W maximum	identical
Operating temperature	0 to +55 °C (+32 to +130 °F)	identical
Non-operating	−40 to +65 °C	identical
Humidity	10 to 90 %, non-condensing	identical
Anode current (average)	< 650 µA	identical
EHT	24 kV ± 1.5 kV	identical
Convergence centre / edges	0.010″ (0.25 mm) / 0.020″ (0.5 mm)	identical
Scan	15.75 kHz ± 500 Hz · 60 Hz ± 5 Hz	identical
Yoke tilt	declination of a horizontal line < 0.10″ (2.54 mm)	identical
⚠️ Tube	V13510YWB22, 19″, 90°	⚠️ 510UTB22, 19″, 90°

ⓘ One line differs across the whole sheet: the tube. Everything else — down to the convergence tolerance and the yoke tilt — is the same specification. ⓘ This is not a maker's data sheet: it is Atari's requirement, which two different suppliers had to meet.

✅ And the connectors are identical, which is the practical consequence:

Video connector, 6 pins	Power connector, 3 pins
1 green · 2 red · 3 blue	1 100 VAC
4 ground · 5 ground	2 no connection
6 ⚠️ negative composite sync	3 neutral

⚠️ The mains is 100 V: these are Japanese-market sets. Putting them on 230 V without a transformer destroys them → mains chain.

ⓘ Both manuals carry a heavy rights reservation — the U.S. Copyright Act of 1976 is cited with its statutory damages. Reproduced here rather than smoothed away.

⚠️ The case this table does not cover: a consumer television

"General Electric Model 25MB color monitor with tuner, IF, and audio modules removed, and with chroma module replaced by Atari unit."

⚠️ A consumer television, stripped of its reception stages, with its chroma module replaced by an Atari board. ⓘ None of the documentation listed on this page covers it — not Wells-Gardner, not Electrohome, not Sanyo, not Sharp: servicing such a set belongs to the television's manual, not to an arcade one.

ⓘ It is also why these cabinets' dimensions surprise: Tank 8 is 44½″ square and 84″ tall with its canopy — a cabinet built around a television set, not around a chassis. → Atari before the microprocessor

Equivalence table (chassis swap)¶

A beyond-repair chassis can be replaced by an equivalent — check tube, yoke (deflection) and frequencies before fitting. Per Arcade Otaku & vendors:

Group (interchangeable verify)	Frequencies
Nanao MS8 / MS9 · Sanwa PM-1745 · Rodotron 666a · Wei-Ya 2931a · Neotec 2702	15/24 kHz, 29"
Nanao MS2932 · Rodotron 666b1	tri-sync (untested against MS2930/MS2931)
Sanwa 29E31S · Wei-Ya 2929 / 2931a	tri-sync 29"
Sanwa PM-1723 B/C/D · Sega 200-5090 / 20V21S	15 (/24) kHz, ~20"

'Equivalent' ≠ plug-and-play

Same electrical family ≠ same connector / yoke / adjustments. Expect to rewire the input (RGB/sync), adapt the yoke if needed and set geometry/focus. A universal Wei-Ya chassis is often the simplest route for an "orphan" tube.

Repair (common method)¶

All of these repair the same way:

HV discharge → CRT safety.
Recap → method; read the BOM off the board (revisions), the big filter often outside the kit.
Reflow (neck, flyback, connectors); HOT / flyback = wear.
Adjust focus / screen (G2) / geometry.

Dedicated chassis pages¶

Nanao MS8 · MS9 · MS29xx tri-sync
Sanwa · Toshiba PB-7534 (Windy 2)
Wells-Gardner · Sanyo 20-EZ · Hantarex
Modern tri-sync (Wei-Ya/Makvision/Kortek)

Archived original documents ✅¶

Documents archived locally, found on Internet Archive on 13 August 2026 and identified from their title page. ⚠️ The items declare no licence.

Procedure — working through a chassis ✅¶

Discharge the anode before anything else

The tube holds its charge with the cabinet unplugged, and so does the main filter capacitor. Discharge it, keep one hand in your pocket, and do not work on it alone. → CRT safety

Hot chassis: the ground is not earth

Some arcade chassis are referenced to the mains. On those, chassis ground is not earth, and an earthed oscilloscope clipped to it makes a dead short through your probe. Work through an isolation transformer. → CRT safety

1. Cold, before switching on. Cracked solder joints are the fault on these chassis — around the connectors, the flyback and anything heavy enough to work its own joints loose. Also swollen capacitors, cooked resistors, the brown halo of something that has been running hot. Reflow what looks suspect before diagnosing: a good share of intermittent chassis faults end there.

2. Fuse and primary side. A fuse that goes again is a short downstream, not a fuse problem — find it before fitting another.

3. Is there EHT at all? The tick of the flyback at switch-on, the filament glowing in the neck. No EHT points at the supply or the line stage. EHT but no picture points at video or the G2 — two very different jobs, and this is the measurement that separates them.

4. Recap — before any adjustment. This page does not carry a single list: take the one for your exact chassis. On a chassis of this age recap is not optional: the electrolytics are thirty years old and have been running hot since day one. → Recap

5. Adjustments, and only now. ⚠️ Never before the recap. Setting the geometry of a chassis whose capacitors are dying records the drift and makes you do the whole job twice. Write down where every pot was before you touch it. → CRT safety

6. Scan rate. This page covers several chassis with different capabilities — take the line for yours from its table. A board whose rate the chassis does not accept shows nothing, and nothing is faulty.

7. Verification. Let it run warm for a good while and check the geometry stops moving. A chassis that is right cold and wrong after twenty minutes is still a thermal fault — usually a joint, sometimes a capacitor you left in.

Sources & attribution¶

Arcade Otaku Wiki — Monitor Chassis Equivalents (equivalence groups) — https://wiki.arcadeotaku.com/w/Monitor_Chassis_Equivalents
arcadepartsandrepair — Monitor Chassis Pictures (Toei TC-RM251S/CM-F20U/CM-14, Neotec NT-2700, Rodotron/Pentranic CH-688A, Wei-Ya C825H) — https://www.arcadepartsandrepair.com/tech-help/monitor-chassis-pictures/
forum.arcadeotaku.com — Toei TC-RM251S repair — https://forum.arcadeotaku.com/viewtopic.php?t=41319

Review & corrections

How this space is used

Spotted a wrong value, an outdated procedure, a chip reference that does not match your board? Say so here, with what you observed (model, board revision, serial number, measurement). Every report is cross-checked against a source before anything changes — an unverifiable correction is published as “reported by …, not cross-checked” rather than silently applied.

Reading is open to everyone; posting requires signing in with Discord. Reports from the wiki's declared reviewers are handled first; anyone else's are read too, but go through a human before anything is changed.