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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...

This is the best schematic i have of the PS. Posting for future reference. Hoping to get a proper manual soon.

I have replaced all but the three big caps in the PS. They are on order, i pulled the big caps out and measured them, they were still within capacitance spec on my meter. i measured the output rails, here are my findings. no more than .2vac on any rail. however there is one rail that has a 25%...

i do now realize that im measuring the "-" leg of the bridge in the photos, i remeasured the positive side and the AC voltage is double.

I was tracing this signal from the amplifier regulator card, back to the bridge rectifier. i understand the caps on the regulator card are supposed to filter this ac ripple somewhat. do i have a bad diode?

Here is a short video of the noise, you can hear the hum in my monitors, its about twice as loud in sync and repro than rec. you can also hear the screeching from the capstan motor, which goes away when i peel the tape from the optical sensor and the motor turn off.