Transistorquestions Wurlitzer 3400 Statesman

Hello everyone!

I have some questions about the transistors in my Wurlitzer.

I have changed the electrolytic capcitors and checked the four "big" transistors, one was shorted and blow fuses, so that one has to be changed.
I´ve read that you have to change them in pairs, but do I have to change all four or is two okey?

And then has some early owner changed two of the small transistors on the pcb to "mini-steel-top-hat" versions,
but both is on the same side (A-channel).... on the other side is one yellow dotted and one green dotted transistor???
Is that right?
I thought that a pair is one on the A channel side and one on the B side, am I right?
There is a sound problem on the A-channel, the sound is almost gone so that might be the problem...

Kind regards: Stefan, Sweden

Hi Stefan,
If I understand you question correctly--no--"pairs" (2) of the (large TO-3, output) transistors are used in each "side".
Do you NEED to change both on one side--No. However, it was suggested that you do-- but, I think it's not necessary---
As for the smaller ones--I'm guessing that they are substitute parts--
Ron Rich

Thanks Ron!

I´ll change the bad transistor and measure again and see what happens.

Stefan

Stefan,
In MOST cases, but not all, the large output transistors "go bad" because of something else. One must determine if that is the case before installing a new one, or the new one will also, go bad, instantly.
BTW--I have the WurliTzer part number 125703 (-5, or "green dot") out puts in stock--NOS-- PM me, if you wish to purchase any--
Ron Rich