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Incoming B-6...Might be a basket case...will need Avionics help for sure !!! FIXED, again !!!

rottalpha said:
I meant, why do you need to test the Sankens on a curve tracer?
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Ohhhh , just to see how they compare to the original Toshibas. Im sure there are slight differences and they might not make any difference where I put them. I wonder if I should split them up amongst the channels or just put them where the blown originals were.

As I side note , my B-dent Toshiba parts came along with the mica insulators.

Athanasios
 
Nashou66 said:
Ohhhh , just to see how they compare to the original Toshibas. Im sure there are slight differences and they might not make any difference where I put them. I wonder if I should split them up amongst the channels or just put them where the blown originals were.

As I side note , my B-dent Toshiba parts came along with the mica insulators.

Athanasios
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so you would have to take them into the breakdown voltage region, right?
or at least test them at operating voltage and current?

How do you plan to do that with the leader or the DCA?

my point is that you are trying a futile exercise. The Sanken are more robust devices and if they are genuine (and they actually look genuine) I would just pop them in, make sure that everything else checks out and fire her up.

Note, IIRC, DBT is a NO NO for X power supply amps. @avionic would give you the rest of the homework, I am sure.
 
Been reading up on curve tracers and matching transistors and most say for Output devices no need to really go through this exercise as you say Rott . So I'll just pop these in as are.

But I still might use the DCA pro just for fun ;)

Athanasios
 
avionic said:
Replace in complimentary pairs..
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What I may do , unless otherwise you think its not a good idea, is to take the all the good Toshiba parts and put them in the amp sections and then the new Sanken parts use them in the switching sections on the two opposing sides of the main PCB .

What say you?

Athanasios
 
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Nashou66 said:
What I may do , unless otherwise you think its not a good idea, is to take the all the good Toshiba parts and put them in the amp sections and then the new Sanken parts use them in the switching sections on the two opposing sides of the main PCB .

What say you?

Athanasios
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A very good idea. I did this in one of my two B-6.
 
Ok, measured the hFE of all transistors.

Here is what I got and How I think I will group them.....not sure it it will make a difference or not.

The Sanken's are much larger and will over hang the metal mounting plates for the switch section of the PS....Will that matter?

52185744790_d32a6e6042_b.jpg


52185275573_cb06247013_b.jpg
 
Nashou66 said:
Here is what I got and How I think I will group them.....not sure it it will make a difference or not.
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I would have been worried if the Sankens were a closer match. Given that you have G and Y ranks, the differences were expected. I doubt it matters if you use them in the PSU section.

Nashou66 said:
The Sanken's are much larger and will over hang the metal mounting plates for the switch section of the PS....Will that matter?
Click to expand...
I do not think it make s difference. The new transistor would not need to dissipate more heat than it's predecessor, so that plate should be enough. The of the new transistor die might be diffused differently but I am still there should not be any issue from a thermal management perspective.
 
Thanks guys.

I removed the drive boards and changing the 3 caps there and going to change the 100 ohm Trim pot.
52185655769_1d2237aa7e_b.jpg



I do think the Sanken's will fit.

Athanasios
 
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Question on a bunch of 1uf 100 volt lytic's on the main board, can you use 1uf film caps or is the polarity needed . I know some replace small value lytic's with films if they will fit.

Is there any benefit in doing so ?

Athanasios
 
Nashou66 said:
Question on a bunch of 1uf 100 volt lytic's on the main board, can you use 1uf film caps or is the polarity needed . I know some replace small value lytic's with films if they will fit.

Is there any benefit in doing so ?

Athanasios
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Don't see why not..
 
While I wait for the trimpots and the film caps to replace the electrolytic's can I power up the
amp with out the main board connected and just the PS section connected to test if its working ok?

Or more importantly, how can I power up the unit with out damaging anything to see if there is any issues beside those I have discovered already by not powering up the unit.

It was mentioned not to use a DBT ( which I dont have anyhow but plan to build one) .

So what is the procedure to test the PS ?

Athanasios
 
Nashou66 said:
While I wait for the trimpots and the film caps to replace the electrolytic's can I power up the
amp with out the main board connected and just the PS section connected to test if its working ok?

Or more importantly, how can I power up the unit with out damaging anything to see if there is any issues beside those I have discovered already by not powering up the unit.

It was mentioned not to use a DBT ( which I dont have anyhow but plan to build one) .

So what is the procedure to test the PS ?

Athanasios
Click to expand...

Well I never got an answer to this question....So Im moving along slowly...I also had a Sansui 7070 I needed to repair in-between .

But I put the trimpots on the small daughter boards and got the recap done on the main board. All 1uf and the .22 uf are now film caps and the other caps are now 105c rated .

52210495653_2c30935683_h.jpg
 
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