Phonoland

Hi all, I am working on customers amp number 61024903 , we recently sold it and it was working fine. One channel developed bad sound. I have seen this before and went right to the fuses on the driver boards. Sure enough one was blown. The new one popped immediately. So I assumed the output darlington transistor was bad. This amp uses 2 ea 2n6287 and 2n6284. We got a deal on all 4 so I got them and installed them on site. Now the amp is totally dead! Even the channel that was ok in the beginning. the only connector that can be put in backwards is the volume control, been there. I had pulled them out one at a time just to make sure that they did not get reversed. I have grabbed another older amp with the same transistors in it and looked at the positions too. There is no bias adjustment on the driver boards, and nothing in the service manual. So at a loss as to where to go on this. Thanks in advance. Mark

Blown outputs usually take drivers, resistors, and diodes along with them.
Just replacing outputs is not an effective or successful repair.
Troubleshooting of the associated circuitry in a static and dynamic way is required.

Hello Mark,

Did you get those output transistors off of Ebay?
Ron said he tried some off of Ebay the other year and they were copies that were bad.
I would get them from a known source.

Regards
Alan