Recent content by happybirthday

Hello all, want to start by saying thanks for all the help up to this point. I have learned so much and yet still tons to learn and a tape machine to fix. I havent given up but had to leave town for work and i was also waiting for a new filter pcb to arrive from tascam ninja as mine was...

Sweet; when i put it all back together pins 13 and 14 are shorted together. This threw me off. 13 and 14 are both shorted to pin 4,5,6 - 0v input from PS, which i believe was the reason for the crazy oscillation in the amp channels (bias signal coming thru the 0v rail) Without the VCO soldered...

Thank you both, this clarifies a lot for me. I understand some of the information i was providing was in accurate and confusing. Here are some findings from today: Recapped the Filter PCB, cleaned the board the best i could, then measured resistance between all the pins, in and out. Found...

My apologies for being unclear. Let me explain for archival purposes. Without really knowing what im doing, i was scoping and metering ac current on the amplifier cards (using a card extender) U and L connectors. (Will post a diagram below) I was looking for ac noise, it showed up on a few...

Yes c2 c4.

At first glance.... i was measuring continuity between the osc output and the 0v rail. didnt make sense that they were shorted. i dunno. Pulled the board out to get a better access with my probes.... holy mackrel, someone butchered this thing Desoldered these caps to see what the brown stuff...

Ok i have a real update... i found the fuckery

im seeing 200mVac on the 0v rail and the bias osc. when using a card extender. im having a hard time catching it on the scope. heres a schem. There is some other mACv hanging around the amplifier but the bias and 0v are the strongest.

Im stumped. Noise on all channels, but coming from the heads??? I need a little push.

that is a great idea, iv been trying to track down a milivolt meter but i cant seem to find one used locally. Will havr to look into this build a bit more.

Mc1468l was the original voltage reg, i replaced it with a Philips equivalent. Heres a little pic of the board that regulates the 15v power Heres the B version schematics. The main 3 caps are the same in mine. I managed to find a 35v 33000uf cap. However i cant locate the other two. 50v...

If i unplug the heads MOST of the noise is gone and the vus return to rest.

I have the “A” model. Orange legs. I own a hard copy of the 85-16b manual. Its mildly useful for PS schematics. The pinouts are similar but the circuit is redesigned. Wrkrbee has a proper manual for me but im having a hard time communicating with him. I got the new chip in the mail and...

I hope you know how helpful it is to have someone like yourself taking the time to write all this out. I really appreciate it. Hadnt had a chance to update but im pretty much following your advice. The Ps is isolated from the rest of the machine until it runs “normal”. I traced the voltage...