Hi,
I am a newly subscribed member having problems with my beloved Eight Deluxe. I had not used it in several months, and when I powered it on it would not energize the protection relay. All fuses are intact. I looked at the service manual and checked for DC on inputs to the protection CB F1475. I found 45VDC on the left channel.
I checked all of the output transistors. They seemed fine. So I swapped the left side driver board for the right side driver board and the problem changed sides. When I remove the problem board, the protection relay will energize.
I have spent a good deal of time doing some on the board checks of at least the discrete components, comparing reading from the good board to the bad board. So far, I have not been able to find any discrepancies.
The service manual seemed to suggest that TR-801, TR-802, TR-803, and TR-807 could be suspect. So I changed these, even though I didn't find any issue with my checks. I also changed the electrolytic caps on the board. Probably not surprisingly, I didn't fix a thing!
Can anyone give me a pointer or two on this? I can send the service manual if needed.
Thanks so much,
DD
Imlay City, MI
I am a newly subscribed member having problems with my beloved Eight Deluxe. I had not used it in several months, and when I powered it on it would not energize the protection relay. All fuses are intact. I looked at the service manual and checked for DC on inputs to the protection CB F1475. I found 45VDC on the left channel.
I checked all of the output transistors. They seemed fine. So I swapped the left side driver board for the right side driver board and the problem changed sides. When I remove the problem board, the protection relay will energize.
I have spent a good deal of time doing some on the board checks of at least the discrete components, comparing reading from the good board to the bad board. So far, I have not been able to find any discrepancies.
The service manual seemed to suggest that TR-801, TR-802, TR-803, and TR-807 could be suspect. So I changed these, even though I didn't find any issue with my checks. I also changed the electrolytic caps on the board. Probably not surprisingly, I didn't fix a thing!
Can anyone give me a pointer or two on this? I can send the service manual if needed.
Thanks so much,
DD
Imlay City, MI