Emilblanca
New member
- Joined
- Dec 16, 2020
- Messages
- 4
Hi folks,
So I bought an otari MTR90 mk2 recently from some hifi warehouse. They told me it was all working and they recorded a record on it - i thought , great, i wont have to do any work on it, good to go...yeah I was wrong, it has a few issues.
Waiting on new rubber rollers restored from Terry, as the orange-ish rubber had pretty much turned to marmalade. also the head shields are completely non op... Someone obviously tried to revive them by the looks of things, to no avail.
Has anyone got a full set of digitised schematics for these things? I have the service manual but it lacks anything useful
finding schems seems to be difficult?
Particularly I need the head shield drive circuitry. I spent a while servicing the mechanism and it can lift and drop fine on a DC bench supply although it needs around 100mA...
I measured what the Otari is trying to pull to drive the little Canon motor and its only 25mA, doesnt seem to have momentum/startup torque to push. I spent all night sorting the mechanism out.
its 24volts so im guessing from the 24v PSU rail..so I could check caps etc (every cap ive tested on other areas has been bang on, although havent tested PSU caps, also havent tested any for leakage either)
I followed the wires from the small motor PCB (white with black dots) and found them to be leading to Pin 25 (one side at least) of Card 3 and 4 (transport control and master CPU). Also I found this, in the same wire grouping just behind the main machine cards, bias etc, behind the side panel. Not sure if its from factory or something weird? Cut wires? Thought it to be odd. can anyone confirm ?
Anyway yeah sorry long winded but I guess I would like schematics for cards 3 and 4, and anything to do with head shields circuit. the SM just talks about lubing the worm gear
So I bought an otari MTR90 mk2 recently from some hifi warehouse. They told me it was all working and they recorded a record on it - i thought , great, i wont have to do any work on it, good to go...yeah I was wrong, it has a few issues.
Waiting on new rubber rollers restored from Terry, as the orange-ish rubber had pretty much turned to marmalade. also the head shields are completely non op... Someone obviously tried to revive them by the looks of things, to no avail.
Has anyone got a full set of digitised schematics for these things? I have the service manual but it lacks anything useful
finding schems seems to be difficult?Particularly I need the head shield drive circuitry. I spent a while servicing the mechanism and it can lift and drop fine on a DC bench supply although it needs around 100mA...
I measured what the Otari is trying to pull to drive the little Canon motor and its only 25mA, doesnt seem to have momentum/startup torque to push. I spent all night sorting the mechanism out.
its 24volts so im guessing from the 24v PSU rail..so I could check caps etc (every cap ive tested on other areas has been bang on, although havent tested PSU caps, also havent tested any for leakage either)
I followed the wires from the small motor PCB (white with black dots) and found them to be leading to Pin 25 (one side at least) of Card 3 and 4 (transport control and master CPU). Also I found this, in the same wire grouping just behind the main machine cards, bias etc, behind the side panel. Not sure if its from factory or something weird? Cut wires? Thought it to be odd. can anyone confirm ?
Anyway yeah sorry long winded but I guess I would like schematics for cards 3 and 4, and anything to do with head shields circuit. the SM just talks about lubing the worm gear
