Repair: Hantarex monitors¶

Hantarex (Italy) = the monitor of European JAMMA cabinets. The MTC-9000 (15 kHz mono-frequency, extremely common) and the Polo / Polo 2 (15/25 kHz auto, later). Standard CRT repair: HV discharge, recap, reflow, and the PSU (Polo).

Identification / range¶

Chassis	Type	Sizes	Frequency	Use
MTC-9000	mono-frequency raster	14" / 20" / 25"	15 kHz	1980s-90s EU JAMMA cabs — the most common
Polo / Polo 2	auto raster	25" / 28"	15 / 25 kHz auto	later EU cabs
9110 / Boxer / 28"	variants	—	15 (/25) kHz	per cabinet

Safety (read first)¶

High voltage — discharge the tube

Lethal high voltage held while unplugged → discharge the anode before work. See CRT safety & HV discharge. Isolation transformer for powered measurements.

MTC 9110 (25″ and 28″) — the multilingual manual, and what it changes about the MTC 9000

The Manuale di servizio / Service Manual / Handbuch / Manual de servicio / Mode d'emploi covers the 25″ and 28″ in five languages.

✅ First contribution: it confirms the MTC 9000 point for point. The four commissioning voltages are identical — TP10 = 130 V DC ± 3 %, TP13 = 26 V ± 5 %, TP1 = 24 V ± 5 %, TP14 = 200 V ± 5 % — as are the 128 V AC through an isolating transformer and the degaussing P34 bridge. ⚠️ This does not settle the 190 V (C205, Thierry 04's guide) against 200 V (TP14, manufacturer) divergence further down this page: they are two different measurement points, and the second document comes from the same manufacturer. It only confirms that the manufacturer's value was read correctly.

Item	MTC 9110
Supply	128 V AC +10 −10 %, 50/60 Hz · transformer primary 120 V (USA) or 220/240 V, secondary 128 V 150 W
Consumption	100 W max.
Degaussing	100 to 264 V AC, automatic
RGB input	positive-going, impedance 2.2 kΩ, sensitivity 1 to 5 V p.p.
Video pass band	−3 dB at 12 MHz
Blanking	horizontal 12 µs · vertical 1 ms
Sync	H and V, positive or negative, composite or separate · 2.2 kΩ · 1.5 to 5 V p.p. · polarity chosen by SW4
Scanning	horizontal 15.625 ± 0.5 kHz adjustable · vertical 45 to 65 Hz adjustable
X-rays	limited to below 0.5 mR/h · D.H.H.S. accession no. 8720899-05

⚠️ Here the chassis and heat sinks are connected to EARTH — the opposite of the Wells-Gardner

Hantarex writes, under the heading EARTHING: "The chassis and the heat sinks are connected to earth. To measure voltages and to inspect waveforms, connect the negative terminals of instruments to the chassis."

⚠️ Wells-Gardner uses the same two words to say the opposite: "the chassis and the heat sink are directly connected to one side of the AC line". Two manufacturers' manuals, the same phrase, opposite conclusions — and one explicitly permits clipping the scope ground to the chassis where the other would make that a short.

⚠️ This is not a question of brand, it is a question of design, and nothing on the chassis says which. The table of every manufacturer position is on CRT safety. Here, earthing the chassis presupposes the 128 V supply through the isolating transformer prescribed in point 1: the two instructions form one whole, they are not taken separately.

A 25″/28″ monitor that cuts out when hot is doing what it was designed to do

The 9110 in 25″-28″/110° carries a thermostat on the heat sink, on the side of the BU 508 transistor. The manual: "The thermostat comes into operation if its temperature reaches 75-80°, interrupting the 130 V d.c. supply so bringing the fault to the attention of the operator. This could happen if, for example, the ventilator failed, or the monitor were used in conditions of extreme ambient temperature."

⚠️ A picture that dies after a few minutes of play and returns once the cabinet has cooled is therefore not necessarily a supply fault: it may be the protection doing its job, and the real fault is the fan. Look for the thermal cause before reaching for the iron.

MTC 9110 — the claimed innovations and the setting-up, as printed

What the maker presents as new:

"monolithic" construction, a single printed circuit board, automatic component insertion;
⚠️ two connectors, CL and CM, for the deflection unit, "with cross-over wiring which permits easy inversion and reversal of the image — often an indispensable feature". Flipping the image is a connector swap, not a rewire — useful for a mirrored or cocktail cabinet;
all picture controls on a small separate board, normally plugged into the main board, usable with a 1.5 metre extension available on request, so you can adjust while watching the screen;
video input through a precision three-gang potentiometer, accepting 1 to 5 V p.p. without changing colour balance;
TDA 1670A for vertical deflection → vertical flyback of 0.7 ms, "so extending the range of logic board usage";
F.D.A. conformity claimed for the X-ray protection.

ⓘ The X-ray protection circuit is described in the same terms as the Sejoo/Eurocoin "Vision": same TDA 2595, voltage fed by a resistive divider to pin 8, tripping beyond 30 kV, the oscillator blocked "until the cause of the failure has been repaired", reset only by a complete power off. Two manuals, one Italian and one Korean, describe the same circuit in near-identical wording — this wiki notes it without drawing any conclusion about who wrote it first.

Manual degaussing — as on the 9000: remove the P34 bridge, insert a twin cable of the desired length into connector CD, terminated in a push-button switch; degaussing then becomes available at any time.

Setting up, in the manual's order:

TP10 = 130 V DC ± 3 %;
horizontal oscillator: remove the incoming sync (you may use SW4) and turn RV5 for a stationary image, then reconnect the sync;
vertical oscillator: adjust RV1 for a slow downward roll, then turn back until it locks;
TP13 = 26 V ± 5 % (vertical deflection) · TP1 = 24 V ± 5 % (video amplifier) · TP14 = 200 V ± 5 % (video output amplifier);
B3 coil: set RV4 on board CG for minimum horizontal amplitude, then the ferrite core of B3 for that same minimum, then go back to RV4 for the amplitude you want;
east/west: preset RV401 on module KK;
RGB output stage gain: equal-amplitude RGB signals in, blue gain RV206 (neck board ZG) to mid-position, then contrast P1 to read 100 V p.p. at the blue cathode; bring red and green to the same value with RV202 and RV201;
white: remove the video signal, RV7 (grid 1) to maximum brightness, black levels RV203 red, RV204 green, RV205 blue to minimum (clockwise); reduce brightness with the grid 2 control on the line output transformer TH2 until the dominant colour is only just visible, then work the black levels for the best white. ⓘ "The G2 'Screen' potentiometer functions as the brightness control."
focus: the FOCUS control on TH2, dot pattern, medium brightness;
horizontal linearity: grid pattern, the last square on the right equal to the first on the left.

Polo 25″ RCA USA — the only document that says where the isolating transformer matters

The schematic and parts list for the Monitor Polo 25″ RCA USA carries, in five languages, a warning more precise than any other manual on this wiki: it bounds the instruction instead of stating it wholesale.

"Whenever voltage checks are to be made in the primary circuits of the power supply, using a digital voltmeter or an oscilloscope, it is necessary to isolate the monitor from the mains supply by means of an ISOLATING TRANSFORMER […]. This precaution is not necessary when making measurements in the monitor section (deflexion and video), nor in the secondary circuits of the power supply."

✅ This is the first time a manufacturer writes down the scope of the rule here: the supply primary, yes; deflection, video and the secondary outputs, no. ⚠️ It excuses nothing — it only says the protection targets one specific place, and that knowing which side of the supply you are measuring is part of the job.

ⓘ And it gives the transformer's specification, which no other does: input 110-120 V AC, output 110-120 V AC, 200 W minimum.

⚠️ The same warning, translated five times — and the Spanish says the opposite of the other four

On the earth of the measuring instruments, this document contradicts itself from one language to the next:

Language	What that version says about the instruments' earth
Italian	"facendo comunque attenzione che la terra degli strumenti sia scollegata"
English	"taking care that the instruments are disconnected from earth"
French	"en faisant […] attention à ce que la prise de terre des instruments soit débranchée"
Spanish	⚠️ "debiendo estar la tierra del instrumento conectada" — and it argues the case: "al estar el instrumento a la tierra se evita dañar cualquier componente y tener la máxima seguridad para el operador"

Four versions say to disconnect the instruments' earth; one says to connect it, and explains why. ⚠️ This wiki does not arbitrate between a manufacturer's translations — but on an instruction that stands between you and an electrocution, a reader who has only the Spanish version should know the other four say the opposite. That is why all five are reproduced.

ⓘ A German version is also in the document; it is not reproduced here, not having been read with the same care as the other five.

Hantarex Polo — the five-language service manual, and what it confirms ✅

The Polo Service Manual I/GB/D/E/F (34 pp.) is the full manual of which this wiki held only the Polo 25″ RCA USA schematic.

✅ It confirms the translation divergence published here — and extends it. The same warning, in the same document, about the earth of the measuring instruments:

Language	What that version says
Italian	"la terra degli strumenti sia scollegata"
English	"the instruments are disconnected from earth"
German	"alle Instrumente vom Erdpotential getrennt sind"
French	"la prise de terre des instruments soit débranchée"
Spanish	⚠️ "debiendo estar la tierra del instrumento conectada"

⚠️ Four languages against one, and now in two separate Hantarex documents. So it is not an isolated misprint in the schematic: it is a persistent divergence of the Spanish version. ⓘ The German is added here — yesterday I declined to quote it, not having read it with the same care.

✅ And an apparent contradiction dissolves. The Polo 25″ RCA USA schematic prescribes a 110-120 V isolating transformer in and out; this manual prescribes 220-240 V. ⓘ Two markets, not two opinions — and both require the same 200 W minimum.

⚠️ The centre pin of the mains connector must NOT be used

"The central pin of the J101 connector must NOT be used, it being of insufficient dimensions to carry the current set by international safety standards."

ⓘ The earth therefore does not go through the connector: it fastens to a threaded metal post on the framework, with the supplied termination, screw and stainless steel washer. The mains cable itself must meet EN 60950 — the manual gives the example: up to 6 A over 2 m at most, 0.75 mm² section.

⚠️ The colour sequence changed between two Polo generations

"Insert the signal input cable into the 6-way connector J106 paying attention to the correct sequence of the colour inputs that is printed on the monitor p.c.b. N.B. the sequence is RGB and NOT BGR as on earlier models."

⚠️ Same maker, same range, and the order is reversed from one generation to the next. This wiki had already recorded that three manufacturers number the colours differently; here, one manufacturer contradicts itself over time. The only reliable instruction is the manual's own: read the order printed on the board, do not trust memory.

ⓘ And an inverted picture is fixed at the connector: "As two connectors (J113 & J114) are provided with cross connexions, the deflexion yoke cable should be moved into the adjacent connector should the image be inverted both vertically and horizontally." The same principle as the MTC 9110 below's CL/CM connectors — at Hantarex, flipping the image is a connector move.

Setting the levels, as printed — and a bridge that fixes one precise defect

ⓘ Polo monitors leave the factory set with optical instruments, on the tube's colour co-ordinates. What follows only serves to redo that pre-alignment.

Black level — ⓘ ten minutes' warm-up, video signal removed:

set the cut-offs on the neck board — RV3 (red), RV4 (green), RV5 (blue) — to obtain 180 V at the collectors of T2, T4 and T6;
contrast RV405 to minimum (anti-clockwise), brightness RV406 to maximum;
raise the G2 (on the line output transformer, labelled "screen") until the raster is only just visible;
remove the predominant colour with RV3/RV4/RV5 for the best grey. ⚠️ If brightness rises, lower G2 until the raster is barely visible again and repeat.

White level — ten minutes, signal removed, brightness and contrast to maximum on the CR board; ⓘ set the "TEST VIDEO" bridge on that board to ON to obtain vertical white lines; adjust RV1 (red gain), RV2 (green gain) or RV6 (blue gain).

✅ Cut-offs on the dark end, gains on the bright end: the same convention as Wells-Gardner and the Sejoo "Vision" — and the opposite of what the Moon Cresta manual prints, a divergence flagged elsewhere on this wiki that remains open.

⚠️ The P152 bridge: against coloured flyback lines

"As supplied the monitor has the artificial blanking circuit unactivated. To activate this function, remove the bridge P152."

ⓘ What it is for, in the manual's words: when the available blanking time is less than 7 µs, "irregular colouration or horizontal fly back lines of differing colours" appear in certain areas of the screen. Removing P152 eliminates them.

✅ And it breaks nothing: "In this condition, the monitor still functions in the presence of a normal external blanking signal."

ⓘ Deflection: the trimmers on the CR remote control board first; trapezoidal or pincushion distortion afterwards, on the EAST/WEST JA board. Both modules carry each trimmer's function printed on the board.

ⓘ Degaussing: automatic at switch-on, 220-240 V ± 20 % in Europe, 110 V ± 20 % in the United States.

MTC 900/E — an earlier generation, and an X-ray protection with nothing in common

The MTC 900/E U.S.A. manual (Hantarex U.S.A. Ltd., 127 Prospect Avenue, Douglaston, New York) covers a 19″ colour monitor in horizontal and vertical versions. ⚠️ It is not the MTC 9000/9110 generation above, and the difference is not cosmetic.

	MTC 900/E	MTC 9000 / 9110
Line IC	Philips TDA 2593	—
Vertical deflection	Philips TDA 2653 A	TDA 1670 A
X-ray shutdown	⚠️ a thyristor (S.C.R.) fired through a divider	TDA 2595, pin 8
Trip threshold	⚠️ 28.5 kV	30 kV
X emission limit	⚠️ below 0.25 mR/h	below 0.5 mR/h
Video bandwidth (−3 dB)	⚠️ 8 MHz	12 MHz

⚠️ The mechanism differs as much as the threshold. Here a voltage taken from the secondary of the EHT transformer reaches, through a resistive divider, the gate of a thyristor; beyond 28.5 kV the thyristor fires and stops the horizontal oscillator. ⓘ As on the 9000/9110, "the circuit continues blocking the oscillation until the break down has been repaired and the supply reset" — but it is not the same component making the decision.

ⓘ The nominal EHT is given as three values — 23 / 24 / 25 kV at 117 V DC, zero beam — where the wiki's other manuals give only one.

MTC 900/E — data sheet, as printed

Item	Value
Mains	98 to 130 V AC — ⚠️ "through an isolation transformer by means of J1"
Degaussing	automatic
Video input	RGB analogue, TTL compatible — 1 / 4 / 5.5 V p-p
Sync	TTL, separate H and V or composite (H+V), positive or negative — 1.5 / 4 / 5.5 V p-p
Horizontal blanking	11 µs
Video	response 8 MHz at −3 dB · rise time 50 ns · overshoot 0.5 to 3 %
Beam limiter	1 mA
Linearity	horizontal ± 14 % · vertical ± 10 % · pincushion ± 3 %
Tube	90°, 19″

ⓘ The instruments are specified: a digital multimeter of 10 MΩ input impedance, and an oscilloscope of stated bandwidth. ⓘ And for a magnetised area the manual points to a manual degaussing coil, despite the automatic degaussing.

Common faults¶

Symptom	Likely cause	Lead
Overvoltage / excessive HV (MTC-9000)	a capacitor goes OPEN (not shorted) → the load is "let go" → +B and HV rise (tube stress)	Recap; measure +B before reconnecting the tube
Flicker / unstable image	dried electrolytics (recap) or the PSU (Polo)	Recap; if it persists → PSU diagnosis
No picture / no HV	HOT, flyback, supply	Check HOT / flyback / +B
Intermittent dropouts	cold solder joints	Reflow
Blur	flyback focus pot	Adjust / replace the flyback

What the Hantarex service manual establishes — MTC9000 ✅¶

Read from the French section of the service manual archived below ("FRANCAIS: de la page 27 à la page 32"). The document is multilingual: the manufacturer wrote those pages, they are not a translation by this wiki.

The MTC9000 does NOT plug straight into the mains

"The monitor must be supplied through an isolating mains transformer with the following characteristics: primary 220/240 V AC; secondary 128 V AC; 100 VA."

The chassis expects 128 V AC +10 % −20 %, not 230. Connecting it directly destroys it. Stated consumption: 100 W maximum.

Item	What the manual gives
Video input	positive RGB, 2.2 kΩ impedance, 1 to 5 V peak-to-peak sensitivity
Video bandwidth	12 MHz at −3 dB
Syncs	H and V, positive or inverted, composite or separate, 2.2 kΩ, 1.5 to 5 V p-p — polarity chosen by switch SW4
Scan rates	horizontal 15,625 Hz ± 500 Hz, adjustable · vertical 45 to 65 Hz, adjustable
Blanking	horizontal 12 µs · vertical 1 ms
Degaussing	220/240 V, automatic at switch-on

The voltages to measure, with their test points and tolerances

The installation, checking and adjustment section does not say "check the supply": it says where to measure and what tolerance to accept.

Stage	Test point	Expected value
Main supply	TP10	130 V DC ± 3 %
Vertical deflection	TP13	26 V DC ± 5 %
Video amplifier	TP1	24 V DC ± 5 %
Video output stage	TP14	200 V DC ± 5 %

The two oscillators are set in this order: cut the syncs (with SW4), turn RV5 for the steadiest picture, restore the syncs — then turn RV1 until the picture drifts slightly downwards, and back off until the drift stops.

The manual confirms Thierry 04's guide — and completes it on one point

The two documents describe the same chassis thirty years apart. They agree:

the 130 V at TP10: the guide gave the value, the manual adds the ±3 % tolerance;
the 26 V at TP13 feeding the vertical stage: identical;
the X-ray protection: above 28 kV, a voltage taken from the EHT transformer reaches pin 8 of the TDA 2595 and blocks the oscillator until the fault is gone — "the monitor must first be switched off and back on to be reactivated". The guide described exactly that behaviour;
SW4: the guide cited it for vertical sync, the manual states it is the sync polarity selector;
manual degaussing: the guide said "cut a strap". ⚠️ The manual names it: bridge P34, to be removed, with wiring inserted into connector CD.

⚠️ And one divergence, published without arbitration. For the video output stage, Thierry 04's guide expects 190 V DC at C205; the manufacturer's manual expects 200 V ± 5 % at TP14. The two measurement points are not the same, and the gap fits inside the tolerance — but this wiki does not arbitrate: both values are published with their source.

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 carries the capacitor list — take the one matching your exact chassis if it covers more than one. 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.

Troubleshooting the MTC-9000, component by component ✅¶

The source, and its reservation — reproduced, not summarised

Everything below is transcribed from the guide Le dépannage des moniteurs Hantarex MTC9000 (11 pp., PDF archived here), written in French by Thierry 04 in December 2006.

The author states what his document is made of:

"This document was put together from information found on the Web and extended with my own personal experience. If you find errors or omissions, do not hesitate to let me know."

And his warning, worth reading in full:

"Repairing monitors (whatever the make) must be done by people aware of the dangers of high voltages and trained to work on such equipment. […] up to 28,000 volts. There is mains voltage in the degaussing circuit and 130 V DC on the chassis. When working on a monitor, use only one hand, to avoid creating a closed circuit between your two hands passing through your chest and therefore your heart! […] I cannot be held responsible for possible errors in this document, for injuries, or for deaths that might result from its use. If in doubt, do not touch it!"

⚠️ The values and references below are the document's own. This wiki has not verified them on a chassis. The author's contacts as he gives them: the.nerv.free.fr (his schematics) and the flippers-jukeboxes.net forums.

Identifying your chassis¶

The guide sorts the range oldest to newest, by visible differences — the only way when the markings are gone:

Chassis	What you see looking at it
MTC90	chassis in two parts with a large gap between them; 4 plug-in cards on the flyback side, 3 on the other
MTC900	two main boards, one of them half-size, plus a small vertical PSU board; sometimes a vertical East-West correction board opposite the PSU
MTC900E	two main boards of equal size; PSU and a triple contrast pot on the left, sweep circuits and the deflection connector on the right
MTC9000	slide switch on the left seen from behind; small vertical pot board in the centre; a sheet-metal heatsink around the flyback
MTC9110	the MTC9000 plus a fan above the flyback and a thermal cut-out — what 25″ tubes demand
POLO	mains-independent chassis (180-264 V/50 Hz in Europe, 80-130 V/60 Hz in the USA), tubes from 10″ to 33″; sheet-metal cover over the switching PSU, on the left

⚠️ Two versions of the MTC900 and MTC900E, told apart at IC3 (frame circuit, behind the 6 pots): TDA1470 on a U-shaped heatsink = version 1 · TDA2653A on an L-shaped one = version 2. "The manuals reflect these differences only in the schematic, not in the cover photographs."

⚠️ A wiring trap on the MTC900: the pot connector is identical to the mains one. Swapping them, the author writes, "is instant failure".

⚠️ The US MTC900E: its connectors are "identical to the Electrohome G-07 connectors" — the chassis this wiki documents on Other chassis.

What the guide gives, fault by fault¶

First of all: look. The author insists — check that every plug is in the right place, and that the black earth wire between the neck board and the braid around the tube is in place.

Symptom	What the guide points at
No "rustling paper" sound at power-up and R105 (330 Ω / 30 W) boiling hot	flyback and/or BU508 shorted. R105 then dissipates ~60 W against a 30 W rating. ⚠️ The fuse does not blow: the protection circuit acts instead — baffling if you do not know it. Check with an ohmmeter between flyback pins 1, 3, 9 and pin 5; swelling or cracks in the plastic confirm it
Flyback replaced	also check R81 (4.7 Ω / 9 W), which often goes with it
130 V missing or wrong (measured on the deflection connector's centre strap, or TP10)	60-70 V → C34 (22 µF/160 V) or C53 (470 µF) · TR20 (TIPL762 or BU508) open · R110 (33 kΩ) — replace with a ½ W, not the original ¼ W
Voltage too high, picture waving	TR20 shorted, or C53 faulty (170-180 V should be across it)
130 V present but no EHT, monitor starts then stops	X-ray protection tripped: above 28 kV, pin 8 of IC2 (TDA 2595) stops the line oscillator. Test: unsolder one end of D10 — if the picture returns, the protection was indeed active. Check C36, C37, C40, C41. ⚠️ "Never leave a monitor running without its protection circuit."
White horizontal line across the middle	IC1 (TDA 1670A) — equivalents TDA 1670, TDA 1675. If it burns, R94 (3.9 Ω) may follow: refit it with long legs, it runs hot and scorches the board. IC1's supply: 26 V on pin 2 via D5 (1N4004), test point TP13
No vertical sync	slide switch SW4, or C18 (10 µF/25 V)
Black screen	TR15 (BU508A), the hardest-worked transistor on the chassis — measure it unsoldered ⚠️ do not lose the insulator under its tab
Horizontal sync failing after 5-10 min	C38 (1 µF/63 V), D5 (1N4004), D4 (1N4148) — intermittent: C9 (100 µF/35 V)
Fuse blowing at switch-on	diodes D19 to D22 — any 400 V / 1.5 A will do (BYV96C, 1N4007)
Brightness varying, 130 V correct	R90 (270 kΩ) open
White retrace lines across the picture	TR18 (BC639) and its surroundings
All-white screen	190 V expected on C205; failing that, R126 (47 Ω) and D15 (BYD 33G)
Picture too narrow and varying / too wide	C42 (4.7 µF/50 V ⚠️ NON-POLARISED) — or the flyback
Brightness at the picture edges	C57 (1000 µF/35 V)
Whistling, or rippling over the whole picture	C34 (22 µF/160 V)
R62 glowing red	linearity coil open
Clicking at any supply voltage up to 128 V	flyback
Settings drifting	RV7 (220 kΩ) — "its value drops sharply with age"
12 V missing on the TDA 2595 oscillator	ZD1 (12 V Zener) shorted

Two adjustments, and one manoeuvre to know¶

Setting the flyback's "screen" control — unplug the video input, brightness to minimum, turn the control clockwise until the grey raster appears, then back off slightly so the screen goes black again. Reconnect the video, set brightness normally, then adjust focus.

Degaussing — automatic on most MTC9000s, at power-up; it needs the monitor left off for about a quarter of an hour to work. To go manual: wire a pushbutton and cut a strap on the board; to go back to automatic, rewire the strap — the button then does nothing.

Removing the EHT cap — crocodile clip on the tube's earth braid, the other on the shaft of a long, well-insulated screwdriver, then slide the tip under the cap, using one hand only. Hold it there a few seconds. ⚠️ Do it again when refitting: "the tube may have recovered its charge after a while, even once disconnected." → CRT safety & discharge

Repair (method)¶

HV discharge → CRT safety.
Recap (method) — ⚠️ many chassis revisions: read the values off your own board (vendor kits vary). Depending on revision, white polypropylene vs blue-box caps; some chassis have a fan over these parts.
Polo: if a recap doesn't fix the flicker → suspect the power supply (PSU) (a documented fault).
HOT / flyback, focus / geometry adjustments.

Cap kits & parts¶

Paradise Arcade — Hantarex Polo kit (Zanen) · Console5 — Polo 25/28 · or a manual read-off + Mouser / TME / Digikey (recommended given the revisions).

Sources & attribution¶

Arcade-Projects / Arcade-Museum / ukVac — MTC-9000 & Polo repair logs (open-cap overvoltage, Polo PSU) — https://www.arcade-projects.com/
Paradise Arcade / Console5 — Hantarex Polo cap kits (BOM cross-check) — https://console5.com/store/hantarex-polo-arcade-monitor-cap-kit.html
Thierry 04 — Le dépannage des moniteurs Hantarex MTC9000, December 2006, 11 pp., archived here — a signed community document (in French), given to the wiki in August 2026. The author points to his own site the.nerv.free.fr and to the flippers-jukeboxes.net forums. ⚠️ His values have not been re-verified on a chassis by this wiki.
Hantarex — Monitors MTC 9000 14″-16″-20″ and MTC 9110 25″ 28″, multilingual manufacturer service manuals, plus the Polo 25″ RCA USA schematic — archived here on 14 August 2026, see the section above. ⚠️ This line had been promising those documents since the page was created; it is finally kept.

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.