dark green for the driver
I meant to say, I see the deep green color and I was not aware of it before, so maybe that is why it looked toasted. I have a few boards here that are well toasted, that started to look like that, but not because of the factory color being differnt.
 
to me your driver boards looked diferent from eachother. I do not think is the lighting and I am not looking at the filter board...I am looking at two B-1 driver boards.
Just an observation...
View attachment 1092614
Yes, there is 2 types of driver boards in there. I have a pair that is light color and a pair that is dark green one.

Managed to finish the boards late last night and do all the adjustments. Everything looks a ok! Adjusted the bias at 80mV and the DC at 0 volt. This is with the SK180 Tokins.

There were multiple issues with this B-1. Now Have to sort the UC-1 unit. The switch issue has settled in and amp turns on and off normally now but the right meter is not moving. I will remove all the mediocre speaker connectors from the back panel and install a IEC power input. While in there will also get to the couple of the switches on that input board. The body of this B-1 is in pretty bad shape, will most likely do a coat of paint.

Also need to get a new relay for the filter board.
Pete, where did you source yours from? I also seen that a board can be made and so able to install modern replacements
 
Pete, where did you source yours from? I also seen that a board can be made and so able to install modern replacements
I have seen them come up for sale on the fleabay US and Hong Kong. I got mine on fleabay US. They come in yellow or transparent pastic casing.
Replacing with modern components would be a good alternative, if you can get an adaptor board.
 
Yes, there is 2 types of driver boards in there. I have a pair that is light color and a pair that is dark green one.

Managed to finish the boards late last night and do all the adjustments. Everything looks a ok! Adjusted the bias at 80mV and the DC at 0 volt. This is with the SK180 Tokins.

That is really good news.
Question: Does SK180 have the same quescent point (~80mV) as the SK77?
You should verrify that.
 
That is really good news.
Question: Does SK180 have the same quescent point (~80mV) as the SK77?
You should verrify that.
That is a good point, but since I don’t have a curve tracer hard to tell with this batch.

I managed to sort out the UC-1 last night. Replaced all the C458 with C1815 and A763 with A1015
For the C1345 I used new C1345F. Meters working well, and was able to calibrate them properly. While I was there pimped it up with some blue LED’s.

At the moment don’t have a distortion meter but was able to do all the calibrations as per manual.
It is middle of summer here and the B-1 gets really hot. Was able to run it for an hour or so and really happy with the results. I will put the SK77 back to do a compare but doing all the work on the drive boards really paid off. The amp sounds sublime

Want to thank you for your help getting the right parts, I decided to get a board for the NF-4 relay. Also changed the ceramic caps on theVfet sinks Panasonic film caps. Here is a pic of the naked beast.
 

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That is a good point, but since I don’t have a curve tracer hard to tell with this batch.

I managed to sort out the UC-1 last night. Replaced all the C458 with C1815 and A763 with A1015
For the C1345 I used new C1345F. Meters working well, and was able to calibrate them properly. While I was there pimped it up with some blue LED’s.

At the moment don’t have a distortion meter but was able to do all the calibrations as per manual.
It is middle of summer here and the B-1 gets really hot. Was able to run it for an hour or so and really happy with the results. I will put the SK77 back to do a compare but doing all the work on the drive boards really paid off. The amp sounds sublime

Want to thank you for your help getting the right parts, I decided to get a board for the NF-4 relay. Also changed the ceramic caps on theVfet sinks Panasonic film caps. Here is a pic of the naked beast.
Congrats, job well done :beerchug:
The blue lights look a bit alien to me, but that is prolly because my eyes are so used with the B-1, B-2 amber lights.
Nice decor too. Is that 10K a 100v version?
 
I managed to sort out the UC-1 last night. Replaced all the C458 with C1815 and A763 with A1015
For the C1345 I used new C1345F. Meters working well, and was able to calibrate them properly.

I was gonna say, one of my meters was out by 2dBs.
I did not have time to rebuild the UC-1...I will do it next time. I did noticed a bunch of old style 458's in there, so I will definetly bo back in there. I wil not change the pots...the original ones adjusted with no issue.
 
I was gonna say, one of my meters was out by 2dBs.
I did not have time to rebuild the UC-1...I will do it next time. I did noticed a bunch of old style 458's in there, so I will definetly bo back in there. I wil not change the pots...the original ones adjusted with no issue.
I didn’t change the pots also, but the right meter was not working. Changing the transistors 2 tantalum and all the electrolytic fixed the problem. I cleaned the power switch and is working normally now.
The blue LED will look more subdued once the faceplate goes in.
I saw somewhere that is possible to built a curve tracer! The guy called it “frankentracer” or something like that.
 
there is 2 types of driver boards in there. I have a pair that
I too have a unit with green boards. I found that some of the FETs on the green boards might have been replaced on my unit
Could you please look or send a closup photo of the two round metal can FETs with the black heatsinks on the green driver boards... I do not have a schematic handy and don't recall the component ID
IMG_20180122_211208265.jpg
Those two. They are not what the schematic calls for or what my other units have....only noticed them on the green boards. I actually cannot find any information on them.

TJ08, is what they are marked with.
 
I too have a unit with green boards. I found that some of the FETs on the green boards might have been replaced on my unit
Could you please look or send a closup photo of the two round metal can FETs with the black heatsinks on the green driver boards...

Hmmmmm

2SJ24.jpg

2SJ24
 
Green boards...hmmm,
So the ones in this unit not officially replacements...Then what are they.
Does anybody know what TJ08 is...I guess I could answer my own question if I pull one and test it. My guess would be that it is a same channel FET, but is it a close match for the sj24?
I guess I will find out at some point. BTW, both boards have same replacement and both boards come from a unit with a failed SK-180 replacement attempt
 
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Does anybody know what TJ08 is...I guess I could answer my own question if I pull it and tested. My guess would be that it is a same channel FET, but is it a close match for the sj24?
I guess I will find out at some point. BTW, both boards have same replacement and both boards come from a unit with a failed SK-180 replacement attempt

My guess is that the TJ08 was early production version of the 2SJ14. I don't think the failed K180 replacement attempt is related.

My guess on the failed K180 attempt is that someone didn't fully understand how to set up for the K180's properly and they failed as a consequence ... but that's just a guess on my part. :)
 
Hello

On all the B1 I have refixed , I never seen V FET marked TJ08

Here is what every driver boards look like :

B1-driver-board-zoomed.JPG
 
I too have a unit with green boards. I found that some of the FETs on the green boards might have been replaced on my unit
Could you please look or send a closup photo of the two round metal can FETs with the black heatsinks on the green driver boards... I do not have a schematic handy and don't recall the component ID
View attachment 1096137
Those two. They are not what the schematic calls for or what my other units have....only noticed them on the green boards. I actually cannot find any information on them.

TJ08, is what they are marked with.
This is strange, on one of my boards those transistors were replaced with MPSU60 motorola.
 
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