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Bought a Sony TA-N7, and now?

Vint Age said:
I wonder what shape the protection relay contacts are in? :scratch2:
Click to expand...

mmm don't know. Will have to check that. Are they prone to failure?

Today i received the large PSU CAN's from Mouser. The look similar to the originals and fit in the available space.
 

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Harolda said:
mmm don't know. Will have to check that. Are they prone to failure?
Click to expand...

Replacing the ones in my B-2's made a world of difference. :thmbsp: :yes:

Today i received the large PSU CAN's from Mouser. The look similar to the originals and fit in the available space.
Click to expand...

Those look very nice ... What will you be doing with the old ones?
 
Vint Age,

not sure yet what i will do with the old ones. Are you interested?

How did the relays make a world of difference to your B-2?

regards
 
Harolda said:
How did the relays make a world of difference to your B-2?
Click to expand...

I had all kinds of intermittent problems like low channel output and no channel output to mention a couple. When I pulled the relays I attached some wires to the pins and powered it with a power supply while I measured the contact resistances. It was all over the place. I did the same thing with a new one and I got consistently low readings of less than an ohm.
 
Thx for the support Vint Age. I will look into this.

In the meantime i am looking for fusible 330R gate resistors. However, i read on AK that one can also use non fusibles for the gate resistors.
Any thoughts about this?
 
Digikey sells them (Vishay/BC Components NFR25/NFR25H), and on this unit I'd replace fusible resistors with the same, if at all possible.
 
EchoWars said:
Digikey sells them (Vishay/BC Components NFR25/NFR25H), and on this unit I'd replace fusible resistors with the same, if at all possible.
Click to expand...

Yep. already noticed, that Digikey is about the only source for these. I already ordered them.

In the meanwhile i finished the recap on the left power board, including replacing fusible resistors, reflowing al joints.

I also replaced the mv12n diodes each with two 1n4148 diodes in series (see pictures). What i noticed that i cannot test the function of two diodes in series, using the diode test function of my digital multimeter. This was the same with the original mv12n. Testing only one 1N4148 diode was ok.

Still haven't found fusibles R127 and R227, is this a hickup in the Manual?
 

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Last edited:
Yesterday i received the sc1173 and SA473 transistors. What is their function?
Next step is to replace these and reflow the last PCB's

330R fusibles not yet received.

Still have to find a nice way to fix new loudspeaker terminals. I think i will glue a black painted piece of aluminum to the inside, for mounting the terminals.
 
Unless you have access to some very high-tech glue, using same for a metal-to-metal bond is never a good idea. If it pops loose (which it will do, given time) then could easily short your outputs and good-bye VFETs. Drilling the chassis and using nuts & bolts would be much more secure. Or rivets.
 
MX117.MC7150 said:
Unless you have access to some very high-tech glue, using same for a metal-to-metal bond is never a good idea. If it pops loose (which it will do, given time) then could easily short your outputs and good-bye VFETs. Drilling the chassis and using nuts & bolts would be much more secure. Or rivets.
Click to expand...

Yep, already decided to screw the aluminum plate.

Waiting for some parts to continue on the amp:
- 330R fusible gate resistors
- 50K bourns pots
- binding posts
- RCA posts
 
Vint Age said:
:lurk:
Click to expand...

Popcorn? not yet ;) Can't wait to listen to the amp, but i have to be patient and take one step at a time.

In the meantime if have this idea of a setup

CDP-R1/DAS-R1 or TTS-8000--> TA-E900 --> SE-P900 --> TA-D900 --> 2x TA-N7B

--> mid/high TAD 2001 BE horn
--> low/mid TAD/JBL Woofer

What is wrong with this you ask yourself? The second TA-N7B and my wife :nono:
 
Today i replaced the fusible gate resistors, the SA473 and SC1173 and reflowed the Vfet PCB on the left channel.

I also upgraded the PSU diodes
 
Great thread. Thanks!

For me this popcorn emoticon means I'm enjoying watching as a spectator. :lurk:

.
 
In the meantime i pickud up another TA-N7B, one channel not working. I hope it is not the Vfets. Price was good so i decided to buy it.

Listening to the TA-E900 now over the kenwood L-1000M. This must be one of the best pre amps ever.
 
Still did not find the time to continue on the restoration of the first TA-N7B.
The second one is running fine, the problem is probably the speaker relay, because at low levels, there is no sound from one channel, but when i turn up the volume a little it plays perfectly.

Does anybody know a good source for the relais, or can they be cleaned?

regards
 
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