Pole Position Monitor Matsushita TM202G Cap discrepancy, what do I do?

Bullwinkle

Member
Joined
Sep 10, 2009
Messages
859
Reaction score
8
Location
Rochester, New Hampshire
Pole Position Monitor Matsushita TM202G Cap discrepancy, what do I do?

I'm recapping my Matsushita TM202G monitor (pole position cab), I pulled one of the caps (C559) and it was rated at 10uf 250v. The Bob Roberts kit has a 4.7uf 250v listed as what should go in for a cap at that location. Knowing there's a possiblity Bob sent the wrong item, I check the manual for the monitor, and the parts list shows a 4.7uf 250v too for that location. So now I'm confused as I know you can go higher with voltages, but I'm pretty sure you can't do the same with Ferad rating. I have never seen this monitor fired up but the cap looked identical to all the others as far as brand and age. My gut reaction is to replace it with whatever was in there. Any suggestions?
 
I just capped a Kortek monitor, and had a similar issue. I emailed him about it, so I'll cut and past out conversation to see if it helps.

Me:

I was installing your cap kit for the Kortek 13/19 monitor today and
noticed that cap C210 is listed on your sheet as a 22uf100v. The cap
didn't match the values of the original looking one I removed from the
board After consulting the manual I downloaded from the web cap C210 is
listed as a 10uf100v cap (the same as the value I removed from the board). I had an extra on hand and used the 10uf100v instead. I have since fired
the monitor back up and played the game for a while and the image is
perfect. Anyway I have included the PDF for this manual so you can look
for yourself. Just thought I'd give you a heads up. BTW it's listed on
page 14.

Bob:

that is a std industry KTA-915 cap value & it looks like you down graded to the 1st edition, but it doesn't make a great difference in home use... they just
don't hold up on location where they are on 24/7. The 10 should last you at
least 5 years, if not longer, with home use. You can bring on quick failures
by down grading with certain cap kits, so that's why you always follow the
cap kit sheet. Many of your caps can be way off from OEM listings from
servicing, as well. Tech one changes a 10uf50v with a 10uf160v... perfectly
acceptable... then tech two sees it's scoping bad & changes it with a
22uf250v... tech 3 changes to a 33uf350v on location because it's all he had
with him & it saves taking it back to the shop. Now a hobbyist comes along
with a shotgun kit & sees the cap is way off from the 10uf50v that it
started out with, so following the cap kit list will pull it back into spec
with any upgrades it has gotten on the street since it was new.

Like I said, you should be okay with that 10uf cap in this case. That is a KTA-915 chassis also & C210 would be 22uf100v. If you had a
10uf100v it was either OEM or more likely someone had replaced it following
the 1st edition manual prior to you getting it.



And FYI, I believe the cap to be OEM because it matched all the other caps around it. Anyway, while I don't quite understand how he got that info, or how you can move to a 22uf instead of a 10uf... I know he knows way more than me about it, and would assume he's right. It's also pretty cool he emailed me back at length about it within an hour or so of my question.
 
Nice, thanks for the info. I did the same thing you did, recapped with what was in there when I pulled it. I'll assume it worked and will work now. If not, I'll know where to look.

Thanks Again
 
Thanks Ken, I went with the one that was in there as I had a spare. Haven't fired it up yet, but with a new flyback, new caps and little burn, should look nice when I do.
 
Also it depends on the function of the cap.
Generally if it's for non-frequency critical filtering, you can up the farad value without too much of an issue.
I've seen more trouble caused by replacing a 105 degree cap with an 85 degree cap... or using a cap with a lower voltage rating.
But as Mr. Layton stated, it is possible the circuit was altered after the schematics were printed, which is why you often see new revisions.
Wells-Gardner, for example, is notorious for schematics and chassis that don't match 100%... that's where an understanding of electronics theory and design comes in handy.
I'm not sure I agree that techs will change cap values from 10 to 22 to 33 etc, at least not a tech that has any common sense.
Most competent techs will reference schematics and data sheets to be sure components are a suitable replacement.

c559 is a 4.7uf@250v and is a filter cap for the 180 volt supply in that chassis, so a 10uf with at least the same voltage rating will work fine.
 
Last edited:
Old Willy, Thanks for the info. When I purchased the caps (the spares I have, not the ones from Bob Roberts), I got all hi-temp ones as the owner of the electrical distributor that I purchased them at said I should. I guess that was fairly sound advice.
 
Good advice indeed, especially if the caps are located next to any high temperature components... ie, big high wattage resistors etc.
 
Back
Top Bottom