22V1001 uneven brightness

MitchO

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So I did a cap kit on the monitor in my Atari Football yesterday, which is a Wells-Gardner 22V1001. Everything looks great except that one side of the monitor is a bit brighter than the other. When looking at it from the coin door side it is the top of the monitor that is too bright. I'm assuming I need to adjust something but I'm not sure what. Does anybody have experience with these guys and can give me a pointer?

Thanks,
Mitch
 
I don't know the exact cause, but from what I've heard it's cap-related. like you have caps that are the wrong rating.

maybe an expert can help you. good luck. :)
 
Hmm...
OK, does anyone have any recommendations of which cap may be the problem child? I would prefer not to have to recap the whole thing if possible.

Thanks,
Mitch
 
If I recall correctly, there aren't very many more than 15 caps on the chassis. 15 minutes worth of work, tops...
 
You mean you did not replace all the electrolytic capacitors?


There's a metal "twist prong" can style electrolytic capacitor C101 that has 4 internal sections. Section "D" of it on the schematic is probably bad. On these style capacitors, if one section is bad, then likely other sections of it are too.
 
If I recall correctly, there aren't very many more than 15 caps on the chassis. 15 minutes worth of work, tops...

Yeah, it's a about a dozen.

You mean you did not replace all the electrolytic capacitors?


There's a metal "twist prong" can style electrolytic capacitor C101 that has 4 internal sections. Section "D" of it on the schematic is probably bad. On these style capacitors, if one section is bad, then likely other sections of it are too.

I got the Bob Roberts cap kit and replaced all of the ones that were included in the kit. C101 was not included in the kit. I just checked Bob's site and he doesn't seem to carry it. Do you know any one that stocks these guys?

Thanks,
Mitch
 
Antique Electronic Supply (www.tubesandmore.com) in Tempe, Arizona is now the sole manufacturer of "twist prong" (a.k.a. "FP") can capacitors. They are using the original 70-year-old Mallory equipment to make these capacitors. They bought the capacitor making machinery from Mallory when they (Mallory) bailed out of the twist prong capacitor business.
 
Antique Electronic Supply (www.tubesandmore.com) in Tempe, Arizona is now the sole manufacturer of "twist prong" (a.k.a. "FP") can capacitors. They are using the original 70-year-old Mallory equipment to make these capacitors. They bought the capacitor making machinery from Mallory when they (Mallory) bailed out of the twist prong capacitor business.

Thanks.
OK, looking at the V1001 service manual it seems like C101 should be a 4 part with the sections at 800uf/125V;200uf/100V;200uf/50V;20uf/200V. I'm not seeing anything remotely close to that on their site. :confused:
What am I missing here? Do you happen to have a direct link to the correct part?

Mitch
 
Thanks, I'll send them an email.

I also found this thread, seems like I'm not the only one looking for this part. I did some searching and it seems like there are a few people that will custom build one for you. I don't know if I want to risk that or not though.

Thanks for all your help. At least I have an idea of what to try now.

Mitch
 
http://www.tubesandmore.com/scripts...EARCH_TREE02=02_MULTI&SEARCH_TREE03=01_FPTYPE

You might have to email them with the specs of the one you need to see what they have that's not listed on their site. Yours is 1-3/8" diameter.

OK, they do not have them. They directed me to some vintage radio forums where I found a guy that makes custom multi-section FP caps. I talked to him and he said the 800uf/125V is a tough one to find, the rest should not be an issue. He found two possible alternate caps a 1000uf/160V or a 820uf/200V but he said these caps usually measure in about 10% lower than they are rated. I told him that the service manual listed the part as safety critical and I didn't know if they would work or not. Ken, do you (or anyone else) know if one or the other would work or be better than the other?

Thanks,
Mitch
 
The 820uf/200v is a better choice for a replacement. Basicly, since the tolerance of the original is +/- 10% (80uf) then the slightly higher rated cap is a near perfect fit. A plus is that the higher voltage rating gives you a greater margin of safety.
 
The 820uf/200v is a better choice for a replacement. Basicly, since the tolerance of the original is +/- 10% (80uf) then the slightly higher rated cap is a near perfect fit. A plus is that the higher voltage rating gives you a greater margin of safety.

Where did you find the reference that the originals are +/- 10%? I can't find it on the cap or in the service manual.

Thanks,
Mitch
 
Where did you find the reference that the originals are +/- 10%? I can't find it on the cap or in the service manual.

Thanks,
Mitch


Well, I wrote 10% but I think it is actually 20%. That is just the standard that caps have to meet. Some caps have a closer tolerance but those will be marked.
 
Well, I wrote 10% but I think it is actually 20%. That is just the standard that caps have to meet. Some caps have a closer tolerance but those will be marked.

Since this is listed as a safety critical part would it have less tolerance than normal or is that more in reference to the voltage?

Thanks,
Mitch
 
The safety critical aspect is speaking to the x-ray protection circuit. If this circuit is altered or any safety aspects overridden it could result in the monitor producing x-rays. The substitution of this cap will not significantly alter the circuit - I'd be willing to bet that it doesn't alter the circuit at all since it will fall within the pre-determined safety margin.
 
OK, the new custom cap has arrived and I have installed it. The picture is incredibly sharp and clear but unfortunately it still has the uneven brightness. It's not real noticable when there is a lot of light in the room but if the lights are off it's fairly noticeable.

I'm debating on whether it is worthwhile to recap it again on the chance I got a bad cap in my last lot or if I should just live with it. But if anyone has any ideas please post them.

I should also put a plug in for Dave at DH Distributors for building the custom cap for me. If you are looking for the 45X0558 cap for a 19V1001 or 22V1001 monitor I highly recommend him. Call 316 684-0050 and ask for Dave.

Thanks,
Mitch
 
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