Phonoland

Hi,

Another newbie question.
My Seeburg M100BL have a MRA1-L6 amplifier and a WRS5-L6 Selection receiver.
Both are in apparently good condition.
Is really a must to replace all (25 amp + 15 select) capacitors? (around $100)
What's the risk is I try to use it without change the capacitors?
I bought a Capacitance tester, so i will check every thing before plug it.

I saw a selenium rectifier in WRS5, Is necessary to replace it too?
What about the 2 caps in the mech?

Thanks
Claudio

If you plan to keep the box for yourself and enjoy it, go ahead and replace all the caps. This will prevent future breakdowns,and give you peace of mind. it will be $100.00 well spent.

Replace the selenium rectifier with a bridge rectifier, make shure that you get one that will handle the voltage and amperage involved.

I agree that ALL caps should be replaced--but that does NOT "rebuild" the units--ALL other "things" should be checked for spec. I do NOT replace the rectifier, if at all possible. When you do that , you MUST fuse the new one on the AC side !
As for the caps on the motor--not necessary--but you should remove the small cap on the front--just cut it loose, if not already done. Ron Rich

Ron, I have to disagree here. The selenium rect in --Seeburgs-- should be replaced.

That rectifier supplies voltage to bias the 2050 tubes (if used) and when those rects fail -so does the bias and tube conduct continuously. If you are lucky you'll catch it in time or the tube will wear out, otherwise it will cook the coil associated with it.

I saw this in Jan 1988 when equipping one of my V's for locations service. I installed a rebuilt TSR-3. During testing at one point there was a buzzing from the credit unit, the buttons stayed down, the scan coil stayed pulled-in and after few seconds the trip pulled in too.

The voltage from the low-Dc rect sank to around -9vdc under load.

On Wurlitzer, R-O or AMI you can wait till the rect fails, if it ever does, but on Seeburgs it really needs to go.

Rob

Selenium recifiers, in my opinion, need to GO..... period.
They're OLD technology, prone to failure, and just plain unreliable in comparison to modern day silicon.
Sure, perhaps a bit of modding might need to be done to compensate for the lower voltage drop of silicon, but the reliability is worth it.
I like piece of mind over anything else.

The smell of a bad selenium rectifier is something you'll never forget.

Guys,
I guess we will "havta" to agree to dis-agree on this one--for Seeburg stuff, at least--
I have probably changed a couple of dozen of the number one step-up coils over the years. I have never been able to attribute it's failure to the selenium. It has always been a "stalled wallbox", or a 2050, which "stayed fired". I think I have changed less then ten selenium's--but I have changed many more of both the other two type "diodes", that have failed, or shorted, or have been "intermittant", in Seeburg equipment---
And, BTW--I do remember that smell, (rotten eggs) from High School !! Yuk !!!! "We" stunk up a whole floor one day--got us out of a test, for the day, only--- Ron Rich

Ron Rich wrote:Guys,
I guess we will "havta" to agree to dis-agree on this one--for Seeburg stuff, at least--
I have probably changed a couple of dozen of the number one step-up coils over the years. I have never been able to attribute it's failure to the selenium. It has always been a "stalled wallbox", or a 2050, which "stayed fired". I think I have changed less then ten selenium's--but I have changed many more of both the other two type "diodes", that have failed, or shorted, or have been "intermittant", in Seeburg equipment---
And, BTW--I do remember that smell, (rotten eggs) from High School !! Yuk !!!! "We" stunk up a whole floor one day--got us out of a test, for the day, only--- Ron Rich

Ron,
Older silicon recifiers in equipment might have been of lesser quality, being more of a "first-generation" thing.
And of course venders have a lot to do with things.
Also, under-rated diodes or diodes running at their limits are more prone to failure.
Good insurance is to over-rate replacement diodes for a given use.
Chances of them ever failing are rare in that case.