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Yamaha CR-600 restoration advice

Measure the voltages around TR801 through TR804 and post results.
 
avionic said:
Measure the voltages around TR801 through TR804 and post results.
Click to expand...
Voltage at base
TR801 -90mV
TR802 +2.5V
TR803 -100mV
TR804 +2.5V

Diode test
TR801 passed, -500mV drop
TR802 passed, -500mV drop
TR803 0L all around
TR804 0L all around

I’m assuming TR803 and 804 are my issue here. If so, I wonder if I have them in backwards as my eager brain foolishly assumed bipolar in a transistor had the same meaning as bipolar in a capacitor. Looks like I need to do some reading up tonight. Whoops…
 
Check fusible resistors FR801,802 and 803. 3.9Ω,220Ω and 22Ω respectively.
 
avionic said:
I need all voltages please. E,B & C

Maybe, maybe not.

Is this a canadian ( 220v) model?
Click to expand...
Diode test:
I had my leads reversed on diode test for TR803 and 804, they both have ~600mV between base-collector and base-emitter (red on base) and 0L the other direction
TR801 and 802 read ~600 mV base-collector and base-emitter with red on base, with leads reversed everything is 0L EXCEPT on TR802 where I get 1.6V base to emitter with leads reversed



Voltage test (black on base):
Upon testing again TR804 is 2.3V at base, base to collector 8.3V, base to emitter 7.5V

TR803 ~50mV at the base, base to collector ~10V, base to emitter 3.75V

TR801 is 55mV at base, base to collector ~10V, base to emitter -55mV

TR802 is 2.3V at base, base to collector 8.3V, base to emitter -540mV

FR801 ~4Ω (my meter can’t go lower)
FR802 218Ω
FR803 22Ω

I don’t believe this is a Canadian model

IMG_2886.jpeg
 
Joolian said:
TR803 ~50mV at the base, base to collector ~10V, base to emitter 3.75V

TR801 is 55mV at base, base to collector ~10V, base to emitter -55mV

TR802 is 2.3V at base, base to collector 8.3V, base to emitter -540mV
Click to expand...
Black meter test lead connected to chassis ground. I use one of the neg. speaker binding posts for a good ground. Then probe the Emitters, bases and collectors with the red meter lead.
 
avionic said:
Black meter test lead connected to chassis ground. I use one of the neg. speaker binding posts for a good ground. Then probe the Emitters, bases and collectors with the red meter lead.
Click to expand...
TR801: Base ~50mV, collector 10.82V, emitter -25mV

TR802: Base 2.32V, collector 10.68V, emitter 1.74V

TR803: Base 51mV, collector 10.68V, emitter 4.24V

TR804: Base 2.25V, collector 10.63V, emitter 9.80V

Thank you for your patience, I was trying to find resources for testing voltage in circuit and only found diode and out of circuit tests.
 
With your black meter test lead still connected to chassis ground. Probe each end of FR802 and FR803.
 
There is a pair of yellow wires coming off of the power transformer. Measure the AC voltage across these two yellow wires.

Also pull one lead of FR801 and measure the resistance across the resistor.
 
avionic said:
There is a pair of yellow wires coming off of the power transformer. Measure the AC voltage across these two yellow wires.

Also pull one lead of FR801 and measure the resistance across the resistor.
Click to expand...
Apologies for the delay, was out of town all weekend.

When you say measure the voltage across the two yellow wires do you mean leads on both simultaneously or chassis -> each wire individually?
 
Joolian said:
simultaneously
Click to expand...
Need to know what the AC voltage out of the power transformers secondary winding (the two yellow wires). Put black test lead on one yellow wire and red test lead on the other yellow wire. Its AC so no polarity.
 
Hmmm. D802 and D803 these are dual rectifier diodes. Remove each one from the board and test them with your multi-meter's diode test function.
 
What I’m assuming is D802 (closest to the transformer) shows 0L with black lead on middle and red on either outside, and ~540mV with black lead on either outside and red on middle

D803 shows 0L with black lead on either outside and red in middle, and ~550mV with black lead in middle and red on either outside
 
reads like diodes are ok, conducts when red probe to anode so 600mV or so, blocks in the other direction so OL
 
mbz said:
A bit left field, are your measurements with function selector set to AUX or TUNER, try with AUX to rule out TUNER issues
Click to expand...
I have had the function selector on AM this entire time, let me get these diodes back in and check those two again
 
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