Marantz 2230 low voltage on J808

[Edwin Ornedo]

Hi all,

I am new to this group and recently got myself a vintage Marantz 2230, it sounded well but I am sure I am missing some ooomph, so after some readings here regarding recapping I took the dive.

I did the recapp on P800 but i am getting only 22.60v on J808 (to gnd) did not replace any diodes but change H802 and H803. have already adjusted the trimpot to max.

I will need advise/help on how to bring the voltage up to 35V on J808 before going any further, it gives me distorted sound.

TIA,

Edwin

 

[catrafter]

Welcome to AK!
If it was OK before you replaced the caps, recheck your work, maybe you installed one backwards.
Why did you replace H802 and H803?

Tom

 

[Edwin Ornedo]

Hi Tom,

Thanks for asking, do you mean one of the caps could be wrongly installed? ( i will double check them).

When I first tested J808 it was way down to 15V so adjusting the trimpot gave me only 22.60v at max turn. I replaced transistors because I was getting -19v on E and B with (black lead to grnd) vol set to 0 and no loads or inputs. I thought it was not giving me proper voltage.

 

[mbz]

do you mean one of the caps could be wrongly installed

possibly installed transistors incorrectly

 

[Edwin Ornedo]

possibly installed transistors incorrectly

I hope i did it right?
and heres for the caps.

 

[Steven Tate]

Looks like you replaced the trimmer. Is it a 4.7k ohm trimmer?

Also, check the data sheet on your H803. Photo looks like the flat side faces the edge of the board. Silk screen calls for flat “front” side to face away from edge of board. Need to verify ECB on that transistor.

 

[Edwin Ornedo]

hi Steven,

I did changed the trimpot, thinking it could be dirty it's 5K ohm (will it be a prob?). I did looked up the ecb and changed it "flat facing away" now, upon power up it showed me 44V so I was happy, then trimmed it down to 35-36V and powered it down. So connecting the source (aux) and speakers then powering it up again sound is there but as i checked the voltage at J808 it again gave me that -19(E) and a -18(B) voltages what gives?...I am using a NTE289A (NPN).

 

[Edwin Ornedo]

I think i got it, the culprit was (me) the jumper wire to chassis at the bottom of P800 from J803, when I removed the board to do my recap. I double checked all my soldering and found that cable to be moving, when I found the voltage at 44V after changing the pos of transistor H803 the amp was sideways and I was able to trim it to 36V but then when I place it on flat that cable must have came loose again. Will proceed now to bias adjustments, some says 5mv some 10mv some even higher like 17mv but strange enough the 71volts have always been stable at J755.

Thank you all for replying i really appreciate it.

 

[Steven Tate]

Sounds like good progress. Measure idle current between J757 and J758. Hopefully, it will adjust to 5mV with R765.