Polytone Mini Brute lll, lV, M-PA

[Doc Stitches]

Can anybody tell me the volts and amps of the large bridge rectifier (BR 121)?

It is 1 1/4 in. square........The smaller one (BR 71A) test OK.

The only schematics I can find are not very helpful.This has a 15 in. speaker and I think it is for a bass? 180 watts.

Thanks
Jim

[Enzo]

I don't know what they used, but at that size, just get one of the very common 35A bridges at 200v or more.

[Doc Stitches]

Thanks Enzo.

Is the red dot on the old bridge the same as the + sign on the new ones?

Jim

[Enzo]

Probably. Often the + corner of a bridge is made different. SOme have push on posts and that one faces 90 degrees from the rest. And some have the + one indented from the corner a little ways. And of course some don;t.

[jrfrond]

Yeah, in that size, just go for the MP3510, which is 35A@1kV. THAT'S a bridge rectifier baby!!!

[Doc Stitches]

Polytone Mini Brute lll/lV/M-PA

Installed new power transistors and new bridge rectifiers....not blowing fuses

now, but now there is a loud hum from speaker and speaker stays sucked "in".

There is no current from + speaker terminal to ground.

Doc :

[J M Fahey]

1) Make and use a serial lamp/bulb current limiter
2)Unplug your speaker now before it dies
3) there are two Polytone basic flavors, a couple sharp pictures and board number would help.
4) Search here to get schematics, they are around.

[Doc Stitches]

Polytone Mini Brute lll/lV/M-PA

Thanks.......will do.

Doc

[rmerc79]

Doc,

Did you every find the schematics? I've been searching myself and no luck so far.

-Rob