Yamaha CA 600 Repair 2026

[avionic]

What I am understanding here is I need to set Bias before mid point voltage or is it visa versa?

Doesn't really matter.

 

[PioneerPro]

MBZ - In regards to your requests. Check orientation of TR601 and TR603 YES, both Emitters are touching on the same track, so they are installed correct.

Resistance at both fuse bottom clips with no fuses in. I am guessing the amp needs to be ON the DBT and ON. Both readings start low them stabilize at about 5.40 ohms.

I 100% did not damage the mica insulators. I removed these transistor only to test them with a MM.

Resistance of FR601 - Starts low and goes up, stabilizes at about 17.5 ohms. If I reverse the MM probes it goes to OL. This is in the board and not desoldered.

Measure to One Decimal Place. Now sure what that means and my MM does not have a setting for that but I have other MM's.
VDC at TR605 Blue = 7.6
VDC at R617 Yellow = 9.17
VDC at Ceramic Cap = 21.0

 

[PioneerPro]

Doesn't really matter.

Are you sure, because in my 12th message I said, I can manipulate VR601 by Changing VR602

 

[Nashou66]

MBZ - In regards to your requests. Check orientation of TR601 and TR603 YES, both Emitters are touching on the same track, so they are installed correct.

Resistance at both fuse bottom clips with no fuses in. I am guessing the amp needs to be ON the DBT and ON. Both readings start low them stabilize at about 5.40 ohms.

I 100% did not damage the mica insulators. I removed these transistor only to test them with a MM.

Resistance of FR601 - Starts low and goes up, stabilizes at about 17.5 ohms. If I reverse the MM probes it goes to OL. This is in the board and not desoldered.

Measure to One Decimal Place. Now sure what that means and my MM does not have a setting for that but I have other MM's.
VDC at TR605 Blue = 7.6
VDC at R617 Yellow = 9.17
VDC at Ceramic Cap = 21.0

Never take ohm reading with power on.

Redo with power off.

Hopefully your meter wasn't damaged

Athanasios

 

[avionic]

I can manipulate VR601 by Changing VR602

There is another issue then.

Yamaha service manual adjusts the DC offset(mid-point) prior to adjusting the idle current(bias). If DC offset adjustment is available.

 

[PioneerPro]

Never take ohm reading with power on.

Redid with the power off and got the same 5.3 to 5.4 ohm readings at the bottom of the fuse holders.

Redid the ceramic resistor with the power off and got 17.5 ohm then I reversed the probes and got 11.1 ohms.

There is another issue then.

Yamaha service manual adjusts the DC offset(mid-point) prior to adjusting the idle current(bias). If DC offset adjustment is available.

Yes, as I stated in post #12 I tried to do the DC offset and turning the VR601 trimmer did nothing on the meter at all.




Have We Decided If The Can Transistors I Replaced Was A Good Move Or Not?

Again - Thanks for all the help guys.

 

[mbz]

Redid with the power off and got the same 5.3 to 5.4 ohm readings at the bottom of the fuse holders.

Is your multimeter reliable?
I can't see 5ohms for that measurement unless solder bridge or mica or...
plz remove the left channel outputs TR613, TR615 and redo measurements ie, black probe to blk spkr connector, red probe to bottom of -B fuse holder, repeat for bottom of +B fuse holder, amp powered off.

Does setting the speaker selector to off have any effect, no speakers connected.

Redid the ceramic resistor with the power off and got 17.5 ohm then I reversed the probes and got 11.1 ohms.

Do you mean the fusible resistor FR601, should be 100ohms though schematic errors do occur, the value will be printed on the body.

VDC at TR605 Blue = 7.6
VDC at R617 Yellow = 9.17
VDC at Ceramic Cap = 21.0

This was about getting TR605 b/c/e voltages
B= 9.17V
C= 12.0V
E= 7.6V

Base and emitter should be -ve values, assumed overlooked.
Possibly TR605 is off since Ve (-7.6V) > Vb(-9.17V)

Left channel outputs need to be reinstalled for this...
Can you clip the red probe to yellow (R617) then with black probe measure voltage at TR605e (blue), amp needs to be powered on with DBT, note sign, expect about +0.6Vdc

 

[PioneerPro]

Is your multimeter reliable?

Not Sure. I will use a different one, see pics.

I can't see 5ohms for that measurement unless solder bridge or mica or...
plz remove the left channel outputs TR613, TR615 and redo measurements ie, black probe to blk spkr connector, red probe to bottom of -B fuse holder, repeat for bottom of +B fuse holder, amp powered off.

Can't find a solder bridge anywhere and MICA's in good shape in tack. -B is 5.7 +B is 5.2 See attached pics.

Does setting the speaker selector to off have any effect, no speakers connected.

Redid with speaker selector set to off.

Do you mean the fusible resistor FR601, should be 100ohms though schematic errors do occur, the value will be printed on the body.

It is directly below the black capacitor in pictures. Labeled FR601 in schematic. Mine appears to be a resistor with color rings around it. I sent a better pic. Whitish one is Left Side and Greenish one is Right side board.

This was about getting TR605 b/c/e voltages
B= 9.17V
C= 12.0V
E= 7.6V

Redid TR605 with Power and DBT on. E = .75 C = .77 B = 1.43

Base and emitter should be -ve values, assumed overlooked.
Possibly TR605 is off since Ve (-7.6V) > Vb(-9.17V)

Left channel outputs need to be reinstalled for this...
Can you clip the red probe to yellow (R617) then with black probe measure voltage at TR605e (blue), amp needs to be powered on with DBT, note sign, expect about +0.6Vdc

Reinstalled TR 613 and 615. Amp On and DBT On, Red Probe on R617 (yellow in your pic) Started out at about 0.06 VCD and slowly went down to .000

 

[mbz]

You understand that the dial/selector in the middle of your MM is used to select the function and also the range for measurements. All pix shown show the meter set on the 200k range, so when you see 5.7 it's actually 5.7k (5700) ohms not 5.7ohms. The meter also displays the kohm symbol slightly above the "5" as a reminder.

We can disregard the damaged mica/outputs shorting theory.

FR601 looks suspect, last pix shows some stress. Pix 2 appears to show in circuit measurement of FR601 giving 63.5k confirming it has failed. Need to replace typically with 100ohm/0.5W with flame retardent coating, mount raised off the board.

 

[PioneerPro]

You understand that the dial/selector in the middle of your MM is used to select the function and also the range for measurements. All pix shown show the meter set on the 200k range, so when you see 5.7 it's actually 5.7k (5700) ohms not 5.7ohms. The meter also displays the kohm symbol slightly above the "5" as a reminder.

MBZ - this is why I didn't want to touch the Offset and Bias, because I am not 100% sure of what I am doing. The other MM, I was using earlier had Auto Settings so I could not read anything except what it was displaying.

I will order new 100ohm/0.5watt resistors, but to make it a worthwhile Mouser order I would like to get any other probable items I need.

What Transistors can I order to replace the TR605 Transistor that I put KSC2690's in and can be a direct fit so I don't have to cross the Collector and Base legs??? No one has told me if I did that right or not???

I would like to replace all 4 metal can Transistors.
I am not sure the MJ15016's that I used to replace the 2SB531's were a good fit or not???
Also what is a good fit for the 2SD371's metal can transistors so I can replace those as well???
I will be getting these all from Mouser.

I am not a technician and more likely will never be. I have had no formal training in electronics. I am a PARTS INSTALLER at best. So please any advice on any parts that need replace is fine with me.

Also you may notice that someone put a second soldered in fuse connected to the fuse holder and the leads of the AC plugs on the back panel. That fuse is put inside of a rubber tube. Other Yamaha CA 600's don't have that, should I take it out?

I would like to replace the Zenor's just for the hell of it too.

 

[Nashou66]

this will help you pick the correct replacement transistors as long as they are still in production.

As ones that are coming to end of life I try to find suitable replacement and update the list .

Use the MJ21193G instead and its complimentary for the 2SD371's the MJ21194G

Also, do have one of the cheap Chinese parts testers? I would get one if you dont. it will help identify if parts are bad or not .

If your going to do this a lot or more often get the Peak DCA75

Athanasios

 

[PioneerPro]

Nashou66, this is the chart that I used to order the two metal can transistors MJ15016 to replace the 2SB531 and I am still not sure if they interchange and I have asked 3 times without and answer. Google AI says it is not a good replacement.

I want to replace Metal Can Transistors 2SD371 but that is not on list you provided.

I don't care of my Mouser bill gets to $100.00 just tell me what I may need?

 

[Nashou66]

Nashou66, this is the chart that I used to order the two metal can transistors MJ15016 to replace the 2SB531 and I am still not sure if they interchange and I have asked 3 times without and answer. Google AI says it is not a good replacement.

I want to replace Metal Can Transistors 2SD371 but that is not on list you provided.

I don't care of my Mouser bill gets to $100.00 just tell me what I may need?

I make the suggestion in the post above. Google Ai is not always right. that chart I use is pretty good.
And those MJ parts are what most use.



Athanasios

 

[PioneerPro]

I make the suggestion in the post above. Google Ai is not always right. that chart I use is pretty good.
And those MJ parts are what most use.



Athanasios

2SD371 is not on the list? Do you have a suggestions for replacing these?

 

[Nashou66]

2SD371 is not on the list? Do you have a suggestions for replacing these?

this will help you pick the correct replacement transistors as long as they are still in production.

As ones that are coming to end of life I try to find suitable replacement and update the list .

Use the MJ21193G instead and its complimentary for the 2SD371's the MJ21194G



Athanasios

Google does confirm its good replacement

read the entire AI link, it explains the complimentary pair for the 2SB531

Here is the data sheet

https://www.onsemi.com/pdf/datasheet/mj21193-d.pdf

 

[PioneerPro]

In Picture #1 This is the first MM I was using.

In Picture #2 the resistor at the base of the TR609 Transistor is burned so I want to replace it. Also the Resistor right at the base of the TR611 transistor is burned. Also I plane to replace the FR601 Fuse resistor.

In picture #3 the resistor at the base but under TR611 looks burned too so I will replace that. And obviously FR601 on this board too.

Can someone explain to me where the Zener Diodes are on these two Main Amp Boards and how many there are. The SM says only one???

 

[Nashou66]

D601 and D603 in the middle of the board to the right of the buss fuse's.

These are 12 volt 1/2 watt Zeners.

 

[mbz]

so I don't have to cross the Collector and Base legs??? No one has told me if I did that right or not???

Crossing the legs is no big deal. Find the transistor that best matches the original and cross legs if necessary