Joust Power supply issue

Austinman

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I have a Joust system that makes a sound from the speaker when I hit the reset button on top behind monitor.


I replaced the 7a F5 fuse Tuesday PM and it did not blow. When I first got the system, there were two hand written notes on the bridge rectifier saying blown F5 fuse (and there was no fuse in the F5 slot) and the other note that seemed to say:

"+5VDC
@4.15 on cpu
cause RAM failure"

I just posted a pic of the system board in question and have updated the initial post
 

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F5 is a 7a slo-blo fuse, and if it is blowing you most likely have a bad BR1 (bridge rectifier or square thing with tabs as you called it) or a bad regulator.

Bad or low +5vdc such as +4.15vdc will give false RAM error codes.
 
I appreciate the info....where would I geta 7a slo-blo fuse (would Radio Shack have them?), and what about a BR1 (bridge rectifier).

let me know if you have any suggestions on where I can get replacement parts.

Thanks
 
You might also check with Modissett. There should be some electonics parts stores in Austin that stock equivalents. Worse case, find a parts store that stocks NTE5340.

Or ship it to me, I rebuild power supplies for $20 + return shipping cost (usually about $5). PM me for details.

ken
 
You might also check with Modissett. There should be some electonics parts stores in Austin that stock equivalents. Worse case, find a parts store that stocks NTE5340.

Or ship it to me, I rebuild power supplies for $20 + return shipping cost (usually about $5). PM me for details.

ken

I think that there is a Mouser location close by Mod IIRC.
 
Joust Wont Power up UPDATE**

I am going to take - and post - a pic of the system board shortly

Also, I put in a 7A fuse and turned it on. no luck, but when I hit the reset button access at behind the rear top panel - at the top - I could hear the speaker and it seemed as if it was going to power up - but nothing on the monitor. I don't think the F5 fuse blew.
 
I think that there is a Mouser location close by Mod IIRC.

Mouser is based down there, but I don't know if they have will call or how it works. They do have a couple Fry's and they stock quite a few NTE parts. Of course there actually stock can be very hit or miss.
 
Joust System Board Pic

this is a pic of the board that did not have an F5 fuse.

I removed one of the hand-written notes (referenced in original thread)
 

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Those steel clad bridges rarely go bad (I wish they all were built so well). But I would replace all the caps on the board. I usually just replace those cardboard wrapped 4700uF caps immediately and the grey 18000uF caps almost every time.

The thing that worries me more are the wires on the connector from the transformer. From the picture, the wires on the right have been spliced. I would worry that they got them correct.

If you have a DVM, use the schematics to determine the correct pairs and check to make sure that the AC voltages going into the power supply match the voltages in the schematics.

ken
 
The thing that worries me more are the wires on the connector from the transformer. From the picture, the wires on the right have been spliced. I would worry that they got them correct.

ken

I agree Ken, looks like the usual burnt wires were cut and spliced. I'll bet the header is burnt too.
 
Interlock on the Joust

Yes. I did not pull it out. I feel dumb for not knowing that it was an interlock and is required to be depressed or pulled out....

anyway, After pulling out the interlock switch, the monitor now will show fuzzy colors for 5 to 7 seconds, then goes black and repeats like that over and over every 5 -7 seconds

No words on the screen and it does not appear to be "booting up" - just stuck in the cycle described above. I cut it off figuring it would end up blowing the fuse.

Anyone interested in it? or ideas exactly what I should do at this point based on this last update?

I just updated this same info on the for sale forum (sorry to have done both forums - I initially posted for sale and when I kept getting tech tips, I realized the discussion was more appropriate for that forum and posted there.

thanks in advance
 
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anyway, After pulling out the interlock switch, the monitor now will show fuzzy colors for 5 to 7 seconds, then goes black and repeats like that over and over every 5 -7 seconds

No words on the screen and it does not appear to be "booting up" - just stuck in the cycle described above. I cut it off figuring it would end up blowing the fuse.

Are there any numbers showing up on the LED on the ROM card. Normally if the board set is running you will get a series of 3 numbers that flash and give diagnostic codes.

Common ones are:
1-3-1 indicating a RAM error, but more commonly a power issue.
2-x-x indicating a bad ROM chip

ken
 
the monitor now will show fuzzy colors for 5 to 7 seconds, then goes black and repeats like that over and over every 5 -7 seconds

Sounds like you are getting the "rug" pattern, then the game resets, then the rug pattern again, etc. The rug pattern is normal during the power on cycle. Do as YellowDog suggests. On the ROM PCB, see what the LED is flashing. It will be a series of 3 numbers, then a short pause, then it will repeat.

This series of numbers will help diagnose where it is getting stuck. On a fully functioning game, this LED will read "0" (zero) when all power up tests pass successfully.
 
The boot failure code is 1-3-4.

Whenever there is an initial indication of a RAM failure in a Williams board, always check the power supply first. It is amazing how many RAM "failures" are fixed by making sure the power is working correctly.

Measure the voltage at the 4 corners of one of the RAM chips.

The voltages should be
Pin 1 = -5V,
Pin 8 = +12V
Pin 9 = +5V
Pin 16 = Ground

The pins are numbered starting in the upper left corner (notch being up), going counter clockwise.

If any of them are low or are fluctuating more than 0.1 V you need to replace your power supply.

ken

PS: This gets posted so often I have it in notepad "sticky" :)
 
Williams Power Supply

How much is a rebuilt power supply? What is the guys name in Central Texas who rebuilds them?
 
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