Recent content by Marc1234

Finally got a chance to work on unit put back all old small transistors everything works perfectly with exception of now not being able to adjust idle current on right side amp but I believe this is due to the adjustable resistor R763 being dirty and I dont have anymore deoxit as soon as I...

I will replace the old transistors I also tested every single one as I removed all tested good and no leakages I will try and work on it Sunday I will also leave the gain matched diff pair or as close to gain matched as I could get thanks again..! I will update after swap

What's strange is I did that exact thing you mentioned I swapped left to right rca and noise stayed in left channel I used ipad doing the same left right swap and no noise does that even make any sense..?

Noise is coming from my phone WTF I used my ipad with frequency generator at 1hz and sounds normal now I sincerely thank you for your insight now since I have already rebuilt left amp should I put old transistors back in or rebuilt right amp so everything matches

I will try another type of input and get back to you

No noise with jumpers in or out with no input signal applied and volume all the way max also used balance control all the way left and right no noise

And I am using a phone as my input signal

I will test that here shortly at halftime of the game and get a response back to you thanks,Marc

Apparently I didn't..? I am not an audio engineer nor do I have any sophisticated repair equipment i do have a decent understanding of electrical components and schematics and I do have a DBT and a decent DMM as stated after I replaced all caps and speaker relay on power supply I recapped and...

I do not know if bias was ok before work when I get a chance this weekend I will re-check bias as per runningdogs post I believe I measured across the wrong jumpers or revision 1 and should have used the revision 2 measurements mentioned above could bias being off affect the noise I am hearing..?

so i recently bought a 2270 that the seller stated was "working" but had been in his aunts barn on her ranch here in central california for the last 35+ years as he stated she had died in the late 80s i bought it knowing that it would probably have issues because at 300 bucks i knew i could...

also would there be anywhere else on p-750 that i should look at for the -46vdc rail getting to the relay besides h-759 remember that this is with main outputs removed on right p-750 and i still get the -46vdc after 2-3 minuets of on time when first turned on the unit comes out of protection...

http://audiokarma.org/forums/index.php?threads/2sa566-and-2sc680-substitutions.287042/ this is the link i used to order h-758 and h-759 on p-750 for marantz 2270 as it was recommended to replace both as a complementary pair so i ordered the pairs that roobarb recomended I.E mje15032g & mje15033g

i have pulled all devices from right p-750 diodes and transistors and found that at higher temperature h-759 fails allowing -46vdc through to the speaker protection relay and kicks it off this is with the main outputs removed this is why we have come to the conclusion in a previous thread that...

so I cant find my previous thread to post along with this but I need help in finding an equivalent transistors for h-758 and h-759 on a 2270 serial #33xxx right side p-750 I’m getting negative -46vdc thru h-759 with main outputs out. Should these be replaced as a matched pair and what would be...