Discussion in 'Exclusively Sansui' started by ghamilton, Mar 31, 2017.
Were the 4 oval caps ever rebuilt?
Balance adjustment without distortion meter - Set VR01 to 2/3 position from max. point & Set VR02 to 2/3 position from min. point
I know. Thanks
OK,...I found a shorted output (NMA1012) transistor. I am going to replace all outputs with the ST replacements. I'm glad I bought some before they ran out.
I'm even going to replace the good ones so all will be ST. However, I don't know which are NPN and PNP. Can you help guys?
Sorry to hear about your AU-919.
NMA1012 is the PNP - Collector of this goes to the -ve power rail
NMC1012 is the NPN - collector of this goes to the +vc power rail
Very Strange, why this became shorted.
Only one NPN and one PNP was bad on one channel. I replaced all outputs anyway. Now on to the transistors on driver board. Is there a way of checking them without taking them out? Also, I,m looking for a 919 modern transistor sub list. Thanks again guys.
I can't find a transistor replacement list here on AK. Can someone help me find it?
Once more Sansui transistor substitutions
Thank you! I knew I saw this before but I couldn't find it. I guess if the exact wording isn't used when searching then no luck. Thanks again!
Ok, TR32 on the driver board is bad. It is 2SB537. The modern replacement is MJE15031G. Here is the link. https://www.digikey.com/products/en?keywords=MJE15031G&stock=1
Are the specs the same? Or is this replacement going to be a compromise?
change both drivers and use complimentary to keep the balance .
If your talking about TR 29-30-31-32 yes I will replace all 4. However, I'm concerned about performance specs. Can anyone tell me if the link on the modern replacement is a good choice?
You really don't have a lot of choice unless you can find NOS originals, the substitutes suggested, although overkill in respect of their basic specs, have the important metal tabs, (TO220 case) which is the same arrangement as the originals. There are other replacements with similar spec's like KSA1220A (PNP) & KSC2690A (NPN) - but they don't have the metal tab (TO126 case) - so your installation of these types needs to take account of this.
Thank you so much Hyperion. I was beginning to think that no one was going to help me.
OK, I will use these modern replacements hoping the performance will not degrade. I am building a list of parts to order. I hope it won't be a big one. Thanks for your help and keep checking back!!
The performance won't degrade - they are very good replacements, just the nerdy perfectionist in me speaking with regards to the differences in the replacements.
Watching and reading along, however never having one of these on the bench deferring input to others that have already been down the 919 roadway.
As you may know I've reconditioned 3 but never had to deal with a seriously faulty one.
Just ordered parts today! Been busy with family matters.
While we,re waiting on those parts, I have a question concerning the noise in the MC stage. So far the only thing that I can think of after checking for shorts or arcing on the traces or bad solder joints,...Is a leaky transistor. I don't hear the noise if the phono cables are unhooked. I only hear the noise in the MC position and with the TT hooked up. The sound is a faint scratchy arcing sound in the right channel. My $1500 Grado low output Statement/reference sounds awesome but you can hear the noise between cuts. Only when I turned the volume past half way with stylus off the record to listen to the noise to try to figure it out did the amp make the zzzzt sound and go dead. Could a leaky transistor on the MC board cause this?
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