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Atari Vector Monitor Repair/Upgrade

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  9.6) STAR WARS Display Problems (continued...)

"D104, 105" changed from "Type-1N914B" to "Type-1N4001".
DO NOT MAKE THE ABOVE SUBSTITUTION AS IT WILL NOT WORK!!!!!

(*) R606 is incorrectly listed in all manual versions as being 1/4W when in reality it is always 1/2W.

Some changes were also due to parts upgrades and/or additional circuitry:

There are several manufactured variations (and many more upgrade variations) of each of the 3 boards (at least 3 for the deflection board and 2 for the other 2) The original designs are labeled P31X and the newer, more fault tolerant designs are labeled P32X. I also recently discovered a small cache of replacement deflection boards labeled P339 so there may be a whole 33X series, too! To add to the confusion, the Wells-Gardner service manual for "19K6400 series color vector monitors" shows a P341 version of the neck board, a P324 version of the HV unit, and a P322 version of the deflection board; I have never seen any of these versions.

Here is how to identify the versions of the boards that I have seen. The deflection boards are P314, P327 and P339. Some P314s were upgraded most of the way to P327s with a small piggy-back PCB on wire "stilts" at the top of the PCB (see "Input Protection Circuit", described later in this document). The neck boards are P315 and P328 (P328 has a brightness adjustment in one corner) and the HV power supply boards are P316 and P329 (P329 has an LED, HV limit pot, and an extra electrolytic capacitor, C22, which is supposed to be 10uF at 63V). After much very disturbing feedback about the performance of the monitors, Atari had all the boards redesigned to be more robust. The P32X (and P339) versions are the newer versions of the boards.

A close inspection of the P339 deflection boards reveals that they are, in reality, P327s with a P339 sticker covering the part number! I have verified that the PCBs are identical but have noticed several (possibly not all) differences between components on the 2 versions. Make the following changes on your P327, put a new label on it and you will have a virtual P339! All other components except for the diodes (didn't check them because they are too hard to read but it is extremely unlikely that any are different) are the same.

Differences between P327 and P339 deflection boards:

If you have a P314 board, in addition to the changes listed above, you should upgrade the following parts.

Differences between P314 and P327 (P339) deflection boards:

(*) The Zanen "Get Well Kit" uses the original specs and does not include these upgrades.

Since the circuits are essentially the same and since I have used 5 Amp fuses in P339/327 boards without any problems, it is safe to say that you can (and more importantly, probably should) put 6.25 amp fuses in your P314 boards at those 2 locations.

The very first run of P314 deflection boards had design defects in them which were evidently identified after the PCBs were produced but before they were populated (I make this assumption because I have never seen a board which did not have the corrections/substitutions on it). Anyways if your board says "85X0147" at the top then it is from the very first batch. Later batches say "85X0147C" (I have never seen an "A" or "B" flavor). The "C" flavor has C605 (.001uF +/-20%, Type-Z5F capacitor) in the upper right corner but since the plain flavor doesn't have a spot for it, it was soldered piggy-back onto R602. Some boards use a .005uF capacitor instead but you should change this to a .001uF if you have the soldering iron out anyway. The plain flavor has ZD100 labeled as R104 and ZD101 as R105, respectively, even though there are always Zener diodes in those spots regardless.

A comparison of the P315 and P329 versions of the HV PCBs and their documentation yields several conflicting differences which are summarized below. The values marked with an asterisk (*) are the ones I suggest you use regardless of which PCB you are working on (with the caveat that the resistors should be "matched"; don't just change the value of one without changing the values of all the others. The capacitor changes can be made individually). If you use all the asterisk marked values, you will upgrade your P315 to a P329 except that you, obviously, won't have the over-voltage protection portion of P329.


+-------+--------------------------------+--------------------------+
|Part # | Value in document or on PCB    | Document/PCB referenced  |
+-------+--------------------------------+--------------------------+
|*C901  | 100uF @  50V Alum Electrolytic | P329 HV unit PCB         |
| C901  | 100uF @  35V Alum Electrolytic | P315 HV unit PCB         |
| C901  | 100uF @  50V                   | TM-183 3rd printing Sch. |
| C901  | 100uF @  35V                   | TM-183 2nd printing Sch. |
| C901  | 100uF @ 100V                   | 19K6400 service man Sch. |
| C901  | 100uF @  35V Alum Electrolytic | TM-183 3rd printing Fig. |
| C901  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing Fig. |
| C901  | 100uF @  50V Alum Electrolytic | TM-183 3rd printing list |
| C901  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing list |
| C901  | 100uF @ 100V Alum Electrolytic | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*C902  | 100uF @  50V Alum Electrolytic | P329 HV unit PCB         |
| C902  | 100uF @  35V Alum Electrolytic | P315 HV unit PCB         |
| C902  | 100uF @  50V                   | TM-183 3rd printing Sch. |
| C902  | 100uF @  35V                   | TM-183 2nd printing Sch. |
| C902  | < part is not referenced >     | 19K6400 service man Sch. |
| C902  | 100uF @  35V Alum Electrolytic | TM-183 3rd printing Fig. |
| C902  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing Fig. |
| C902  | 100uF @  50V Alum Electrolytic | TM-183 3rd printing list |
| C902  | 100uF @  35V Alum Electrolytic | TM-183 2nd printing list |
| C902  | < part is not referenced >     | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*C905  | 33uF  @ 160V Alum Electrolytic | P329 HV unit PCB         |
| C905  | 33uF  @ 160V Alum Electrolytic | P315 HV unit PCB         |
| C905  | 33uF  @ 150V                   | TM-183 3rd printing Sch. |
| C905  | 33uF  @ 150V                   | TM-183 2nd printing Sch. |
| C905  | 33uF  @  63V                   | 19K6400 service man Sch. |
| C905  | 33uF  @ 150V Alum Electrolytic | TM-183 3rd printing Fig. |
| C905  | 33uF  @ 150V Alum Electrolytic | TM-183 2nd printing Fig. |
| C905  | 33uF  @  63V Alum Electrolytic | TM-183 3rd printing list |
| C905  | 33uF  @ 150V Alum Electrolytic | TM-183 2nd printing list |
| C905  | 33uF  @  63V Alum Electrolytic | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*C915  | .001uF +/- 20% Type Z5F        | P329 HV unit PCB         |
| C915  | .001uF +/- 10% Ceramic         | P315 HV unit PCB         |
| C915  | .001uF                         | TM-183 3rd printing Sch. |
| C915  | .001uF                         | TM-183 2nd printing Sch. |
| C915  | .001uF                         | 19K6400 service man Sch. |
| C915  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| C915  | .001uF                         | TM-183 2nd printing Fig. |
| C915  | .001uF +/- 20% Type Z5F        | TM-183 3rd printing list |
| C915  | .001uF +/- 10% @ 500V Ceramic  | TM-183 2nd printing list |
| C915  | .001uF +/- 20% Type Z5F        | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
| C919  | < part is not referenced >     | P329 HV unit PCB         |
| C919  | < part is not referenced >     | P315 HV unit PCB         |
| C919  | < part is not referenced >     | TM-183 3rd printing Sch. |
| C919  | < part is not referenced >     | TM-183 2nd printing Sch. |
| C919  | < part is not referenced >     | 19K6400 service man Sch. |
| C919  | < part is not referenced >     | TM-183 3rd printing Fig. |
| C919  | < part is not referenced >     | TM-183 2nd printing Fig. |
| C919  | < part is not referenced >     | TM-183 3rd printing list |
| C919  | 10uF @ 300V Alum Electrolytic  | TM-183 2nd printing list |
| C919  | < part is not referenced >     | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R901  | 3.9  +/- 5%,   3 W             | P329 HV unit PCB         |
| R901  | 2.2  +/- 5%,   2 W             | P315 HV unit PCB         |
| R901  | 3.9,           3 W             | TM-183 3rd printing Sch. |
| R901  | 2.2,           2 W             | TM-183 2nd printing Sch. |
| R901  | 3.9,                           | 19K6400 service man Sch. |
| R901  | 2.2  +/- 5%,   2 W             | TM-183 3rd printing Fig. |
| R901  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing Fig. |
| R901  | 3.9  +/- 5%,   3 W             | TM-183 3rd printing list |
| R901  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing list |
| R901  | 3.9  +/-10%,   3 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R907  | 3.9  +/- 5%,   3 W             | P329 HV unit PCB         |
| R907  | 2.2  +/- 5%,   2 W             | P315 HV unit PCB         |
| R907  | 3.9,           3 W             | TM-183 3rd printing Sch. |
| R907  | 2.2,           2 W             | TM-183 2nd printing Sch. |
| R907  | < part is not referenced >     | 19K6400 service man Sch. |
| R907  | 2.2  +/- 5%,   2 W             | TM-183 3rd printing Fig. |
| R907  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing Fig. |
| R907  | 3.9  +/- 5%,   3 W             | TM-183 3rd printing list |
| R907  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing list |
| R907  | < part is not referenced >     | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R910  | 6.8K +/- 5%, 1/4 W             | P329 HV unit PCB         |
| R910  | 12K  +/- 5%, 1/4 W             | P315 HV unit PCB         |
| R910  | 6.8K                           | TM-183 3rd printing Sch. |
| R910  | 12K                            | TM-183 2nd printing Sch. |
| R910  | 12K                            | 19K6400 service man Sch. |
| R910  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| R910  | 12K  +/- 5%, 1/4 W             | TM-183 2nd printing Fig. |
| R910  | 6.8K +/- 5%, 1/4 W             | TM-183 3rd printing list |
| R910  | 12K  +/- 5%, 1/4 W             | TM-183 2nd printing list |
| R910  | 12K  +/- 5%, 1/4 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R911  | 4.7K +/- 5%, 1/4 W             | P329 HV unit PCB         |
| R911  | 6.8K +/- 5%, 1/4 W             | P315 HV unit PCB         |
| R911  | 4.7K                           | TM-183 3rd printing Sch. |
| R911  | 6.8K                           | TM-183 2nd printing Sch. |
| R911  | 6.8K                           | 19K6400 service man Sch. |
| R911  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| R911  | 6.8K                           | TM-183 2nd printing Fig. |
| R911  | 4.7K +/- 5%, 1/4 W             | TM-183 3rd printing list |
| R911  | 6.8K +/- 5%, 1/4 W             | TM-183 2nd printing list |
| R911  | 6.8K +/- 5%, 1/4 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+
|*R926  | 2.2  +/- 5%,   3 W             | P329 HV unit PCB         |
| R926  | 2.2  +/- 5%,   2 W             | P315 HV unit PCB         |
| R926  | 2.2,           2 W             | TM-183 3rd printing Sch. |
| R926  | 2.2,           2 W             | TM-183 2nd printing Sch. |
| R926  | 2.2,           2 W             | 19K6400 service man Sch. |
| R926  | < part's value is not shown >  | TM-183 3rd printing Fig. |
| R926  | 2.2,           2 W             | TM-183 2nd printing Fig. |
| R926  | 2.2  +/- 5%,   2 W             | TM-183 3rd printing list |
| R926  | 2.2  +/- 5%,   2 W             | TM-183 2nd printing list |
| R926  | 2.2  +/- 5%,   2 W             | 19K6400 service man list |
+-------+--------------------------------+--------------------------+

The good part of all this is that the 3 basic units, deflection board, neck board, and HV board are all interchangeable as units and they are all connectorized. In other words if you have one working monitor you can try the boards from your bad monitor (one at a time) even if the boards are not exactly the same. Also, the most often failing components are common to the different versions of the boards. If you have a vector monitor based game, it is really worth the effort and money to have a spare monitor handy (even if it is being used in another vector game) so that you can isolate exactly which board is bad when (not if) you have a failure.

Obviously, the neck board must be physically switched to be tested but you you don't have to unscrew the ground wires of the current PCB, or screw in the ground wires of the replacement PCB; you can just let the current PCB dangle and use alligator clips to connect the replacement neck board's ground wires to the chassis. With careful placement you can test a deflection board or HV unit without having to remove the one already in there. For the replacement HV unit simply connect the 3 connections and then use an alligator clip to ground the case to the chassis. Since you have grounded it, there is no need to attach it to the chassis; simply let it dangle by the secondary anode wire (the one with the suction cup) or the alligator clip but make sure it doesn't touch anything it shouldn't (keep the exposed underside of the PCB from touching anything). The replacement deflection board can sit on top of the current one separated by a piece of cardboard or other non-conductive material but getting it in there is more hassle than swapping so I usually pull the one that is in there and do a swap.

NOTE: There is 1 small exception to this universal compatibility rule for the neck board PCB. The P328 version uses a third (purple) wire running from the innermost (normally unused) pin of connector J501 to pin 8 of J900 on the HV unit. Without this wire, the new brightness control on P328 is disabled. Also, and this is VERY important, if you are using a P328 PCB on a P315 wiring harness (or vice-versa), you have to turn the J501 connector upside down. Don't worry too much about remembering the orientation because the connector's pins are gapped differently so it will only fit onto each PCB one way (the right way) without severely bending the pins on the neck board PCB (i.e. it is idiot-proof). This means that for testing purposes, you can swap boards and everything will be fine but if you want the functionality that the P328 potentiometer provides, you must remove the associated wiring harness that connects to J501 along with the board (or else add a new wire to the existing harness on the destination monitor). Without this wire, a P328 will behave exactly like a P315 and the pot will do nothing.

The very first thing you should do is check all the fuses in the machine with a meter. There are 4 on the deflection board and most Atari machines have 7 more in the power supply at the bottom of the machine (6 in a bay on the left and one under a black cap on the right). Remember to check resistance on the fuse HOLDER NOT ON THE FUSE. Many times a fuse will meter out OK but it isn't making good contact with the fuse holder so it is not conducting. If you always put your probes on the fuse holder, you will never get tricked by a bad contact. Many times fuses not conducting can be made to do so merely by reseating them after pinching the fuse holder clips tighter. Sometimes the clips are corroded and need to be cleaned first. The wire contacts connecting to the fuse holders may also not be conducting properly so you may want to move your leads and test there to cover all your bases. This rule applies to fuses in general anywhere you find them.

The only other components (besides the tube itself) are the six large TO-3 package transistors mounted to the chassis ("package" refers to the physical description of the transistor, NOT the electrical characteristics). The 3 NPNs are 2N3716s and the 3 PNPs are 2N3792s which are all in the final stages of the deflection amps or the power supplies. The deflection amps are like an audio push-pull amplifier and to power these amps the monitor takes AC in and produces plus and minus DC voltages.

Most of the failures in this monitor (as is the case with most electronic devices) are semiconductor failures, specifically, the transistors. All transistors discussed in this document can be tested in the same way; it doesn't matter if they are the large chassis-mounted transistors or the tiny PCB-mounted transistors. With the transistors out of circuit, set your multi-meter on Rx1K scale and use the following procedures.

NOTE: ANALOG AND DIGITAL MULTI-METERS REQUIRE DIFFERENT TESTING PROCEDURES FOR TRANSISTORS! For some reason, digital meters always show infinite resistance for all 6 combinations (if you accidentally get your skin involved it will show something around 2M Ohms). The best way to test transistors with a DMM is to make use of the "diode test" function which will be described after the analog test. For both methods, if you read a short circuit (0 Ohms or voltage drop of 0) or the transistor fails any of the readings, it is bad and must be replaced.


  9.7) TESTING TRANSISTORS WITH AN ANALOG OHMMETER

For type NPN transistors, lead "A" is black and lead "B" is red; for type PNP transistors, lead "A" is red and lead "B" is black (NOTE: this is the standard polarity for resistance but many multi-meters have the colors reversed; if the readings don't jive this way, switch the leads and try it again). Start with lead "A" of your multi-meter on the base and lead "B" on the emitter. You should get a reading of 2.5K Ohms. Now move lead "B" to the collector. You should get the same reading. Now try the other 4 combinations and you should get a reading of infinite Ohms (open circuit). If any of these resistances is wrong, replace the transistor. Only 2 of the 6 possible combinations should show a resistance and that value should be 2.5K Ohms; none of the resistances should be 0 Ohms (shorted).


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