CR1020 Restoration Guidance

Really great work so far! I recently acquired a CR-1020 that had been worked on in the past. This thread has been an excellent guide and also a great repository for related material and links. I have completed a power supply rebuild of my unit and everything is working normally, however, I noticed that the previously "repaired" main filter cap board may have an incorrect value in place for the main filters. They are currently 15,000uF 63V. The schematic shows 18,000uF 71V? I am curious to know what the correct value should be in a CR-1020 and if the 63V rating is sufficient or if it is risky to run in this state.

Also of note: I had 10 ohm fusible resistors too. I swapped them with the 33 ohm ohmite units recommended by oilmaster, rear mounted on board.Schematic shows 33 ohm. Wondering if the hifi engine version is incorrect or if Yamaha just downsized a few power supply components on certain models to cut costs.

Sorry to hijack the thread...
 
They are currently 15,000uF 63V. The schematic shows 18,000uF 71V? I am curious to know what the correct value should be in a CR-1020 and if the 63V rating is sufficient or if it is risky to run in this state.
Typo in the schematic... The SM parts list matches whats installed. 15,000µf/63v...
 
The CR-2020 shares the same board . The 2020 has the 18,000µf/71v.
 
Also of note: I had 10 ohm fusible resistors too. I swapped them with the 33 ohm ohmite units recommended by oilmaster, rear mounted on board.Schematic shows 33 ohm. Wondering if the hifi engine version is incorrect or if Yamaha just downsized a few power supply components on certain models to cut costs.

I really can't say why they were 10ohm.
 
I really can't say why they were 10ohm.
Because you are working on and CR-1020.
. I swapped them with the 33 ohm ohmite units recommended by oilmaster,
Part of the CR-2020 service bulletin

The 1020 and 2020 share the same PCB's for the E-cap and power supply board.But that doesn't mean they are populated with the same components.
 
Wow, this is an awesome thread..........as I have a CR-1020 showing up via USPS tomorrow, I really freaked out! :eek:

Rex
 
I had to Google "Eroticon 6", and now I see you're casting aspersions on my avatar, DDDonna, who by the way is NOT a whore!
DDDonna is my motorcycling muse, I ride a Triumph Tiger 1050, which is powered by a Triple-licious 3 cylinder engine.

In other news, the Yamaha CR-1020 has arrived and it does need work.

Rex
 
Hi Folks;
Please feel free to re-direct me, but I have a CR-1020 in front of me. I am a 'newbie' but wanna-be vintage audio rescuer. I have read this thread an other here at AK but hoping for some guidance;
I have the typical hum on all inputs, that disappears when the bypass switch is opened. I have replaced all caps on the capacitor pcb ( except the large main B+ and - caps). TR715 was removed and tested good. It was re-installed as this repair is on a budget.
My + & -25 Volt pins on the power supply pcb measure 30 V DC with approx 0.5 volt sawtooth. The voltage on emitter of TR715 and collector of TR712 is low; 34 V instead of ~38 V.
The orange resistors R801 and R802 say and measure 10 ohms---say why is the voltage low??!!

Pardon my butchery, but when I raised the line voltage to about 135 vac (briefly) to get emitter of TR715 up to 38 volts, the hum went away.
Just wondering if the low input to the regulators along with the high output, is something that the more experienced folks here at AK have come across. Thanks, Peter in Canada
 
Thanks for your quick reply, avionic. I will lift the fuse-resistors and measure them. I am puzzled that both 25 volt ( + & - ) supplies are high.
 

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