Yamaha CA 1000 power supply
- Thread starter Jodyb
- Start date
B+ reading 50.6 volts B- reading 51.3 volts DC
301 reading 1.98 volts 302 reading 1.99 volts
303 reading 19.5 volts 304 reading 20.8 volts
305 reading 12.6 volts 306 reading 13.5 volts.
I did notice when I touch my meter on 302 I do get mild buzz feedback through the speakers volume down all the way also have the same thing on 303.
Taking the measurements across the legs black on one leg red on the other just to make things clear.
301 reading 1.98 volts 302 reading 1.99 volts
303 reading 19.5 volts 304 reading 20.8 volts
305 reading 12.6 volts 306 reading 13.5 volts.
I did notice when I touch my meter on 302 I do get mild buzz feedback through the speakers volume down all the way also have the same thing on 303.
Taking the measurements across the legs black on one leg red on the other just to make things clear.
Maybe consider building an audio probe.
Will need another amp, anything will do.
Take an old/cheap RCA cable snip off one end, strip core wire and connect to a blocking cap say 0.1-1uf
Connect RCA to AUX input of other amp, select AUX, set vol to minimum
Connect a ground wire between other amp and CA-1000, use the phono GND connections
Connect minni-grabber or similiar to other end of blocking cap and test points on CA-1000 eg,
Power amp IN pin, also try OUT pin. Slowly wind up the volume on the other amp, listen through
headphones connected to other amp
Will need another amp, anything will do.
Take an old/cheap RCA cable snip off one end, strip core wire and connect to a blocking cap say 0.1-1uf
Connect RCA to AUX input of other amp, select AUX, set vol to minimum
Connect a ground wire between other amp and CA-1000, use the phono GND connections
Connect minni-grabber or similiar to other end of blocking cap and test points on CA-1000 eg,
Power amp IN pin, also try OUT pin. Slowly wind up the volume on the other amp, listen through
headphones connected to other amp
Black test lead to be fastened to metal chassis ground........!
Probe the transistors collector leads with the red test lead.
Last edited:
Gents I built a audio probe tonight and finally got time to get back to the amp. I started with the function board it was clean sound to the tone board. Checked the tone board clean on all connection points in and out. (Volume board and in on the filter board are still clean sound). I did notice the out on the filter board was distorted on the left side only. So I did narrow down where its coming from now it seems to be tr501/tr503. I turn the audio control all the way on the left this way I wasn't testing anything I was on the right side it's playing through the board clean and out to the rear panel.
I need to mod the audio probe so I will have easier access for testing need the tip to be a little longer.
Should the sound from all three legs on tr501 and tr503 be the same clean coming out?
I did re-clean all the control switches just to eliminate thinking it was the controls.
In your experience have those transistors burnt out frequently? C1345
Also Avionics thank you for the info on the audio probe didn't take to long to figure out what board it was the problem next will try and narrow down where the problem is.
Im like a kid in a candy store probing everything. Lol
I need to mod the audio probe so I will have easier access for testing need the tip to be a little longer.
Should the sound from all three legs on tr501 and tr503 be the same clean coming out?
I did re-clean all the control switches just to eliminate thinking it was the controls.
In your experience have those transistors burnt out frequently? C1345
Also Avionics thank you for the info on the audio probe didn't take to long to figure out what board it was the problem next will try and narrow down where the problem is.
Im like a kid in a candy store probing everything. Lol
Attachments
The muting switch can be troublesome. Probably best to probe the base of TR501,3,5 and if necessary compare
with the right channel (TR502,4,6). Also the output from the filter board goes to the troublesome coupler switch.
The 2SC1345 has some history of going noisy, some people pre-emptively replace them with KSC1845.
Susgest confirm TR505b is distorted.
with the right channel (TR502,4,6). Also the output from the filter board goes to the troublesome coupler switch.
The 2SC1345 has some history of going noisy, some people pre-emptively replace them with KSC1845.
Susgest confirm TR505b is distorted.
Credit where credit is due.
So thank you both very much for all the help and walking me through the repairs. I'm learning some important lessons and appreciate the patience. Hopefully this post will help other people.
It was TR501 causing the distortion problem. So removed tr502 from the right side and installed on the left side sound cleared up. I do have some 1845 just want to make sure that it is installed in the correct orientation.
This audio probe is the best tool to find problems and fast. Im hopefully starting the complete rebuild next week when the new parts arrive. I am going to try document and photograph the complete process maybe it will help some other members like the both of you guys helped me.
Cheers Jody
My next big problem is to compare the Yamaha to my Marantz 2325.
Wondering if I could also get some pointers on how many recievers to keep lol. Seems to be an addiction I enjoy listening to all the different makes and models but getting a large pile of vintage systems that have been cleaned up and tested.
It was TR501 causing the distortion problem. So removed tr502 from the right side and installed on the left side sound cleared up. I do have some 1845 just want to make sure that it is installed in the correct orientation.
This audio probe is the best tool to find problems and fast. Im hopefully starting the complete rebuild next week when the new parts arrive. I am going to try document and photograph the complete process maybe it will help some other members like the both of you guys helped me.
Cheers Jody
My next big problem is to compare the Yamaha to my Marantz 2325.
Wondering if I could also get some pointers on how many recievers to keep lol. Seems to be an addiction I enjoy listening to all the different makes and models but getting a large pile of vintage systems that have been cleaned up and tested.
Many AKers are reluctant to build the probe, think they just want their amp "fixed asap" and not waste time building probes.
The transistor icons on the filter board are correct (there is an error on the tone board with TR304).
The original 2SC1345 are probably the outhouse shapped, pinout ecb when looking at front bevelled face, the printing
is on the larger back face
If they look like these. The center pin is the collector.
back face shown above.
When looking at front face, push/bend middle/collector pin away from you..
