WG6100 Help Needed

The_Director

Active member
Joined
Jun 11, 2013
Messages
132
Reaction score
73
Location
North Carolina
So, Tempest went down on us again. Has LV2000 installed, cap kit, etc. etc. from previous owner. We had an issue last week with the AR2 board which has been rectified. This time it was monitor problems, blew fuses F100 and F101. I found two shorted diodes in the bridge configuration. Replaced all those diodes, and now its not blowing fuses, but LV2000 only has one LED come on and monitor has a horizonal collapse. The LV2000 LED on the R101 side is the one not lighting. I get positive voltage from pin 3 on P100 pin, but no negative voltage on pin 6. Any help would be appreciated - thanks in advance!
 
Do you have negative voltage going into the LV2000?

If so, then the LV2000 is likely bad. Contact vector-repair.com, and Jeff will usually replace it for free.
 
Or LV2000 negative LDO sees a short on the output and is going into thermal shutdown (caused by over-current).

Check for a short.
Check the chassis transistors.
 
Chassis transistors all good, not shorting to chassis. Not getting any negative voltage on pin 6 of P100. What's the best place to check for negative voltage in line before the LV2000?

One thing I guess I should add, and maybe this is the issue. We didn't have any 5A2 or 1N4007 diodes, so I used some 6A4s which are a higher amperage and voltage rating. Used for rectification though with the way the circuit is built, I didn't think the heavier duty would matter that much, especially since the Zanen kits come with the heavier voltage rated 1N4007s rather than spec 5A2. Could this be a problem?

Thanks again!
 
Red and Black wires are the inputs (+/-33VDC approx).

lv2000.jpg
 
I'm sorry, pin 6 is a dead short to ground. LV2000 is not shorting to ground, double checked with my better meter rather than my crappy one.
 
It's a dumb thing, but I've seen a couple with this same symptom, which turned out to be a bad solder connection for the input wires to the LV2000. The wire they included with the kits is a very stiff solid core wire, and I found solder didn't like to stick to it well. I always replace it with better stranded wire, when I see it. Check both joints, at the board and on the LV2000.

Other than that, the circuit is pretty simple. The incoming voltage gets rectified and filtered to make the -33, so if it isn't a shorted diode, then the LV2000 is toast. This is actually not an uncommon failure. I've seen half a dozen or so.
 
The negative -33 on LV2000 and pin 6 are both dead shorts to ground. I'm guess that means LV2000 is toast?

Now you need to disconnect the black wire and measure the negatives again (on the LV2000 and on the deflection board).
See if the short only remains on the LV2000.

Ideally, at this point, I would remove the LV2000 completely and do the impedance testing on it independent of the deflection board. I would also ohm out the power rails to make sure no short remains on the deflection board.

A short on the -33V input (to GND) should be taking out your associated fuse.
 
OK, replaced LV2000 and its def working fine. Everything from monitor looks correct but I have a collapse still. Pic attached. Any ideas? Thanks!
 

Attachments

  • IMG_7598.jpg
    IMG_7598.jpg
    186.7 KB · Views: 12
Bad frame transistor, bad transistor on deflection board, or possibly no Y output from the game board.

Measure the AC and DC voltages on the YOUT pin of the game board. you should have roughly somewhere between 0 and 1V of DC, and around 2V of AC, give or take half a volt or so. If you have neither of these, the Y output is dead.
 
It's printed on the deflection board (at least for P314, not sure which rev you have). The left side says 'X amp' at the top, which I believe is for horizontal orientation, so that is the Y axis for a vertical monitor.

Q700/1/2 are MPSA06. Q703 and Q704 are MPSU57 and 07, respectively, and can be replaced with ZTX753 and 653, respectively.

You want to verify signal from the game board first though, before the monitor. Feel the chips in the video section (near the pots) with the back of your finger. If any of them are scorching hot (like the TL082's or 1495's), they are bad and need replacing.
 
So, did a deflection board rebuild and rebuilt the entire X amp circuit on the deflection board. We swapped in a known working board from a friend's Tempest and it still had collapse, so I'm guessing it has to still be on deflection board?

Could it be a harness issue by chance? On deflection board, LV2000 is working and putting out proper -26 and +26 at pins 1 and 6 respectively on P100. All bottle caps seem fine, none are shorted to chassis and they all get + or - 31vdc respectively. X amp has been completely rebuilt and a decent amount of the Y amp, new rectifer diodes, all caps are within a year old.

Running out of ideas what to analyze next. Let me know if you guys have something I could try -- thanks so much for all the continued help!
 
Check your wiring. Make sure there's continuity for the X signals from the deflection board to the deflection board. Use your DMM's continuity function to do this.

When you say 'completely rebuilt', what do you mean specifically? If the negative rail for the LV2000 was dead originally, there is likely a bad component somewhere. You want to test all of the parts you remove(d), to determine what failed. Shotgunning parts is not recommended with these boards, as you run the risk of introducing new problems, while trying to solve the existing one.

Also, you want to test the frame transistors properly, using the diode test mode of the DMM to test the junctions. Just checking to verify that they are not shorted to the frame is not enough. Google how to test a transistor, if you are unfamiliar.
 
It's printed on the deflection board (at least for P314, not sure which rev you have). The left side says 'X amp' at the top, which I believe is for horizontal orientation, so that is the Y axis for a vertical monitor.

Q700/1/2 are MPSA06. Q703 and Q704 are MPSU57 and 07, respectively, and can be replaced with ZTX753 and 653, respectively.

You want to verify signal from the game board first though, before the monitor. Feel the chips in the video section (near the pots) with the back of your finger. If any of them are scorching hot (like the TL082's or 1495's), they are bad and need replacing.

Andrew, I could be wrong but I think what you are saying is that X is X relative to the monitor when mounted in a horizontal position. When you mount the monitor vertically in a Tempest cabinet, you need to check the "X" section of the deflection board for vertical image issues and the "Y" portion of the deflection board for horizontal. However, when you get to troubleshooting issues that may be in the game board, you need to check the "X" section for horizontal image problems and the "Y" for vertical. This can be a little confusing to first time trouble shooters. The "X" and "Y" swapping is done at the Tempest board. The way I read your statement seemed to imply that it is in the Y section of the Deflection. However, you did list the correct parts so I know that you know what you're talking about. Just wanted to clarify for the newbs.

Probably clear as mud now. So, after all that, since the OP tried the deflection board in another working game with the same issues I would say something is bad on the left side of your deflection board. Check the 2 transistors on the black heatsinks, (Q703,Q704) as mentioned above. Also, check the diode under them (D702) and the small transistors above the 2 heatsinks as Andrew mentioned.

You are looking for cold solder joints, broken components, solder bridges, bad solder pads lifting etc. Did you try wiggling the red connector at P700 while the monitor is powered up to see if you get the image back? Check all the components with your multimeter in the "X" section of the deflection board. Did you check fuse F700 out of circuit? It may look good but be bad.

I know I repeated a lot of what Andrewb suggested, just wanted to reiterate it is in the "X" section of the deflection board.
 
Pat, I think we're in violent agreement.

FYI for the uninitiated, the monitors were made independently of the games they were put in, and were made with 'traditional' TV terminology, where 'X' is the longer axis of the two. So the monitor's deflection board's 'X amp' silkscreen label is indicating the long axis, which is the Y/vertical axis for Tempest.

The Tempest *PCB* (and each Atari vector game board) uses terminology relative to that specific game. So for Tempest, the YOUT signal on the game board is the long axis signal, but for Space Duel, YOUT is the short axis. (Which may seem confusing, but I'm actually glad they did it this way, as IMO it would be even more confusing the other way.)

But yeah, that's why I specified the components. ;)
 
Back
Top Bottom