Atari Vector Monitor Repair/Upgrade


  4.2) Deflection board pinout

Here is the complete pinout of the main connector (on the deflection board):

  1. Red input (4.0V full on; 1.0V black level)
  2. Green input (4.0V full on; 1.0V black level)
  3. Blue input (4.0V full on; 1.0 black level)
  4. Red GND (twisted pair with Red input)
  5. Green GND (twisted pair with Green input)
  6. Blue GND (twisted pair with Blue input)
  7. X input (16V Peak-to-Peak; 2.5Kohms)
  8. Y input (12V Peak-to-Peak; 2.5Kohms)
  9. Not Used (Key)
  10. X GND (twisted pair with X input)
  11. Y GND (twisted pair with Y input)
  12. Power GND
  13. 25V RMS
  14. Power GND
  15. 25V RMS

SPECIAL NOTE: The 2nd printing of TM-183 has a typo in Figure 8 on page 11 which incorrectly identifies the heater as existing on pins 5 and 6. Strangely enough, both the 3rd and the 1st printings have the correct numbers; go figure.

I should also mention that the monitor Sega used in it's vector games (Electrohome's G08-CB0) is also an analog monitor and can be used in any Atari vector game (and vice-versa) with the proper adaptors to mate the different wiring harnesses (connectors) plus some circuitry to scale the voltage ranges of the analog signals and the AC supply. I do not have documentation for the G08-CB0 so I cannot say exactly what scaling is required but I can tell you that I have seen G08-CB0 monitors with "Tempest" burned into them and I also saw a Wells-Gardner with "Space Fury" burned into it. I have talked to several people who claim to have seen such a setup in action but they have no specifics. I would appreciate any details anybody can provide about the G08-CB0 and/or the specific conversion details (either direction).

David Shuman <essayes@telerama.lm.com> had this to say about the G08-CB0:

"Sega XY monitors are analog monitors like the Atari XY's. Unlike the Atari XY's, the Sega XY's don't have a "Z" channel. The connector from the game board to the monitor has only six connections: R, G, B, X, Y, and GND. The G08, unfortunately, is a thoroughly screwed-up design. The original G08 was apparently an operator's nightmare, often consuming itself in flames. Sega started shipping revised monitors with some hacks added, presumably to improve reliability. The result didn't work too well either, and it looked like Frankenstein's monster with parts hanging off everywhere, gobs of glue, soldered connections where detachable connectors are required, etc. In the first two months I had my Eliminator, I had to fix the monitor twice. And since you can't disconnect the HV board from the main board, you have to be very careful not to twist and yank out the wires as you make your repairs. Picking off factory-installed globs of glue to access blown parts is no fun either."



I know this is supposed to be about Atari monitors but here is some information the Sega color vector monitors that I found on page 12 of the November 1981 issue of the Star*Tech journal. I'll include it here just in case you have one of those hybrid setups mentioned above. If anybody knows more about the redesign that is mentioned, please let me know!

Gremlin/Sega reports that all of the problems encountered with the industry's first color X-Y game "Space Fury" have been identified and solved [yeah, right].

The problems are centered around [ack, bad puns, too!] the deflection (X-Y) amps. Under-rated power transistors combined with an extended "on" time during the power-up routine resulted in damaging the amplifier circuit.

The remedy includes a modification to the card cage and replacement of the Electrohome Monitor with a redesigned unit.

Gremlin/Sega will have replaced all defective monitors and modified all game card cages by the end of October.

Initial field fixes did not resolve the problem entirely and Gremlin/Sega decided to undertake the monitor replacement program.

Electrohome, the monitor manufacturer, will replace monitors in the Eastern U.S., while Gremlin/Sega will handle the Western U.S.

For further details contact your distributor.


Chapter 6) Did Amplifone solve all of Wells-Gardner's problems?

The Amplifone was commissioned as a replacement to the infamous, failure-prone Wells-Gardner. Unfortunately it had a horrendously unreliable Achilles' heel; the HV transformer. This part is widely (but falsely) believed to be impossible to replace because there are no more HV transformers around. Fortunately, this is incorrect and they are readily available, even though they are a bit expensive.

"NOTE: [Ob-anally-retentive-pet-peeve] This part is commonly but improperly referred to as the "flyback" transformer. This is a misnomer because the flyback transformer exists only in raster monitors' deflection circuits. Part of a flyback's duty is to regulate the currents necessary to make the electron beam "fly back" to the left (or top) during retraces. In vector monitors, the high voltage transformer is a "flyback" transformer in the sense that it is constructed and designed just like the flyback transformer in a raster monitor with the exception that the flyback portion (the horizontal deflection coil) is not needed and so is not present. There is an oscillator circuit that serves the purpose that the horizontal oscillator would in a raster monitor, and there is a power transistor that would be called a horizontal output transistor if it were in a raster monitor, but the part of the transformer that controls the retrace (flyback) is not present so there is no true flyback transformer in a vector monitor. If you must give it a name, use "HV" or "horizontal driver" instead of "flyback"."
As soon as Atari heard about all the failures of the HV transformers, they commissioned a third party to supply them with a ton of replacements for the Amplifone monitors since they were so unreliable and in such high demand. Unfortunately (for Atari), by the time they were manufactured, nobody cared anymore (because the games that used the Amplifone were getting old and starting to be retired/converted anyway or else they had Wells-Gardner retrofits in them) so this fact is not widely known to most people in the industry.

The replacement HV transformer was over-engineered to the max so that it would not fail as much as the original part and to date Atari reports that THEY HAVE NOT HAD EVEN ONE REPORT OF THE REPLACEMENT EVER FAILING! To be critical, this could be due to the fact that by the time the replacements became available, most people were no longer routing their Star Wars machines (or at least not with the Amplifone monitors in them). Any machines being repaired and used today are likely to get gentle home use which naturally lengthens the life of the monitor and its parts.

  6.1) No HV?

If your HV is dead then it is probably either resistor R12 near the HV transformer or the HV transformer itself. CHECK THE RESISTOR FIRST since it is much easier and cheaper to replace. Simply unsolder it and see if it has the proper resistance (2.2K Ohms). You will also want to check to see if the over-voltage protection circuit is misadjusted causing it to activate even though the HV is in a tolerable range. If LED (CR2) is lighted, then the over-voltage protection circuit is activated. If it is on then you either have a misadjusted potentiometer or a damaged HV circuit. Mark the initial position of R19 and tweak it a tiny bit to see if the LED turns off. Don't move it too much or you may damage other parts of the circuit or even your tube if the HV is indeed too high.

The catch is that Atari replacement parts are only supplied at the wholesale level to official Atari game distributors. To find out the distributor closest to you so that you can order this part from them, call Atari at 408.434.3700 and give them you Zip or Area Code and they will give you a business name and phone number. I am pretty sure the MSRP is about $160 but that is significantly cheaper than buying a Wells-Gardner retrofit that you will have to repair about once a year (most distributors discount such old parts below the MSRP so you shouldn't have to pay that much especially if you comparison shop and play the distributors off each other).

Starting with some information I provided to get him started, Tim Tewalt <tewalt@peaks.ENET.dec.com> in mid-1995 attempted to bypass Atari and the distributors by buying factory direct. Here is what he discovered:


"Hi guys; bad news. The bottom line is $150 each when ordering a total of 25 flybacks. As Gregg Woodcock pointed out, Penn Trans of Wingate PA, is no longer in business; hell, there's no such thing as Wingate, PA, either for that matter. I called the Postmaster in Bellefonte, PA and found that Wingate was swallowed up by Bellefonte and more importantly, Penn Trans was bought out by Wintron Inc. The part number 926862802 from my flyback, matches the Wintron flyback part number, so I was pretty sure I had found the source. They faxed me a quote a few days later with a price of $173.13 each on a quantity of ten and $149.83 each on a quantity of twenty-five. NOT the deal I was looking for. So anyway, I have decided not to pursue this any further. If someone else would like to look into this, you'll find some pertinent information below. Thanks a lot for your interest, guys. Sorry I wasn't able to come through."

"Flyback" Transformer for Amplifone XY monitor

Atari part number: A201005-01
Type number: 926862802 ("Transformer Multiplier")
Manufactured by: WinTron Inc.
276 Spearing Street Howard, PA 16841 1-800-865-5351 (814) 625-2720 http://www.wintrontech.com

[NOTE: The reason for the high prices is that they do not have any stock on hand and would have to retool the machinery to manufacture a fresh batch. Perhaps it would be simpler and cheaper to get the spec from them and find out what it would cost to have a professional wire one up by hand...]


If your HV transformer is dead then you will need to order Atari part number A201005-01. This part was available in inexhaustible quantities from Atari until recently but now Atari claims they have no more. I suspect that with all the reorganizations of the company some of the "dead weight" inventory was liquidated or thrown out altogether. If you make enough phone calls to large distributors, you should be able to locate one. If you do, please let me know and I'll add the information to this document. One person reported that when his HV transformer went bad it took VR1, R20, and CR5 with it so you may want to test/replace these parts, too (they are commonly available).

  6.2) Installing the Amplifone HV transformer

Here is the document that describes how to install an Amplifone HV transformer. Thanks to Keith Jarett (keith@tcs.com) for mailing me a photocopy (who in turn wishes to thank Mark Sherman and Al Vernon of Atari Games for their fabulous in-depth knowledge and tech support. I agree; these guys have helped me a few times, too, and are fantastic).


[NOTE: To my knowledge, Atari never bothered to copyright these instructions and they are not marked with a copyright symbol.] INSTALLING THE NEW AMPLIPHONE [sic] HIGH VOLTAGE TRANSFORMER

  1. Remove the defective flyback from the highvoltage [sic] P.C.B. [NOTE: The new transformer has a black case and it is smaller than the original which has a red case]
  2. Change R12 to a 1K ohm [1/4 Watt] resistor. [NOTE: recommended for durability; not strictly required]
  3. Secure the new flyback to the high voltage pcb using the mount hole, tighten nut on the circuit side of the High Voltage P.C.B. [NOTE: It bolts through the PCB, though you will have to first: ]
  4. Solder the thick BLACK wire from the HV transformer to the TOP connector on the Focus block.
  5. Feed all six color coded wires from the bottom of the HV transformer through the 2nd hole to the circuit side of the high voltage pcb.
    1. Solder GRAY wire to the point labeled Filament. (see figure below) [NOTE: Pin numbers are shown on the white plastic bottom of the old transformer and on the schematic if you have one; for this reason, I will not attempt to draw in the picture mentioned here] [NOTE: This is where the "extra" wire from the old flyback went.]
    2. Solder ORANGE wire to [former] pin 1. [NOTE: The photocopy I got with my replacement had the label for this pin cut off! It is the pin that goes to the case of Q3.]
    3. Solder GREEN wire to [former] pin 4.
    4. Solder BLACK wire to [former] pins 6 & 7.
    5. Solder YELLOW wire to [former] pin 8.
    6. Solder RED wire to [former] pin 9.

    [A picture showing a full scale drawing of the solder side of the HV PCB, has been omitted for obvious reasons. It does not show anything that cannot be derived from the included text; it was merely a "visual aid".]

[NOTE: End of document; here is further advice from the Atari techs...]

After you finish, you will need to adjust brightness (bottom pot on the white module). Use the self test screen for this. Also adjust focus. If nothing happens, the other (lower) focus wire is broken like mine was [NOTE: Mine was broken, too!]. Take off the rubber cap to verify. Focus is the top pot on the white module. This connection is fragile and takes a lot of heat/current so it frequently breaks off.

Adjust R7 (the frequency of the primary switching) to get a video B+ of 180 volts. According to Mark, this will give the correct HV. You don't really need to tweak R17 as described in the manual if you know that your over-voltage protection cutoff is working OK. Recheck focus after tweaking R7.

If any problems occur, verify that the +24 and -24 volt regulators are reasonably close to the correct output voltages. Some departure is OK if you have the 5 watt resistors bridging their inputs and outputs (these are present to relieve the load under transient conditions such as the all-white death star explosion).

The board should now run MUCH cooler. I can comfortably touch all the HV heat sinks which was not true before.


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