I have noticed that the 24v supply is low (about 22v), but nothing I do seems to correct the problem. I have replaced all capacitors in the poower supply circuits. I also replace ZD1. Do you think the supply could be causing the LED problem? The amp works as it should in all the modes.
SOURCE: Two Jamo MPA-101 amps not working
I can almost guarantee that you'll find bad electrolytic caps on the power supply board to be the cause of the problem. I've seen several of these with the same problem. The protect circuit stays latched due to excessive ripple.
SOURCE: Jamo MPA-101 2 channel amp quit working
Check the small electrolytics on the power supply board for high ESR, Very common problem on these amps. Protect circuit stays latched due to high ripple from PS.
SOURCE: I'm replacing a JAMO amp.
The 201 is 100w in to 4ohms and the 101 is 50w into 4 ohms other then that there the same
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to achieve 24V, you need 24V +0.6V (drop from Q1),
blinking could be U6A? and or associated components
i was referring to the value of ZD1
Tanks for the help. I have repalced ZD1 with a 24 volt zener. It was bad origionaly and the amp didn't work at all. If I pull Q1 I have 24 voots on the diode, but as soon as I hook Qi back up the voltage drops to about 20 volts. I noticed that R90 seem to get hotter than it should also. Qi checkes ok with a DVM diode check. Could that still be my problem even though it checks ok. As a trouble shooting proceedure could I remobe Q1 from the circuit and jumper cathode of ZD1 to the emitter junction of Q1 to see if the 24 volts would be there, or would the impedance of the circuit cause that idea not to work?
Sorry about the typos. I should proof read befor sending.
replace Q1, if voltage on emitter of Q1 would still be 22V ,
then there could be a leak on some of the components after the emitter
on most when zener diode fails it will take Q1 also to fail,
zener value should be 24V + 0.6 V to attain an output of 24V (emitter of Q1) normally speaking.
Thanks for your help. I will replace Q1. I feel that that should correct the problem.
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