Discussion in 'Yamaha' started by sajjad amer, Feb 8, 2018.
TR610 Collector is 28.5, just disengaged the Mute button, still no output at speakers, I am afraid.
ok, I am expecting delivery from digikey and will report back , everything else so far has passed your inspection ?
I was kinda hoping it was a missing the 30 volt ( 28.5v) power supply voltage.
Took out the cap from circuit and measured
V Loss, 6.8,
Which Transistors specifically drive the relay? Should I check them just in case ?
Do you own a set of headphones ?
Just check the solder connection on TR805. I you wish..TR804 and 805 are the drive transistors. The pass transistor TR805 normally runs very warm and over time fatigues the solder connections.
yes, just checked with headphones as well, static when inserting the jack in A and B. Nil else. Has Rec Out Selector any bearing on the sound output, I have kept both selectors on Aux, and using laptop sound card as source at AUX.
That violet cap is bad 9 times out of 10.
ok, will replace the cap and report back. I have 47uf, 50v in my kit, can I use it momentarily to check if every thing works? I have reflowed the solder on TR805
Check or reflow your balance and volume control solder connections.
I will, do it now and report back
It will alter the delay time,but should work.
Replaced the cap as suggested, now the relay does not click at all, despite multiple on/off cycles
I guess it won't work then...Have to wait til you get the proper cap.
ok, will report back with outcome, thank you ever so much for your time, I appreciate it . \regards Sajjad
Or, the protection is working correctly. More times than I care to admit, when I've thought a protection circuit might be messed up, it was doing it's job and protecting me from something else that was wrong.
Also find R725 and R726.. One end of each of those two resistors should have + 28-30vdc and the other end should be .68 vdc ..
The relay circuit is actually doing its job. @ConardH you are right.
When the radio is properly tuned in, upon switching it on, I hear FM radio for a sec and then relay clicks and silence !!!
If Radio is not tuned in I hear a Loud Thud and Silence !!
R725 - one end is 28.3 other end is 0.62
R726 - one end is 28.3 other end is 0.73
OK...find R802 and R803 ( 47 KΩ ) in the protect circuit. Check for DC voltage on both ends of each resistor. Should be close to zero volts ( + or - 50 mv or less) on either end.
The voltage your looking at is the DC offset of each amplifier circuit.
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