BilboBaggins
Addicted Member
Last year, I found a very nice looking Aiwa M700B at the grand opening of a new thrift store. This is the first deck I actually wanted to get working, so I ordered a belt kit. Then, while I was waiting for the belt kit to arrive, I asked a local electronics company if he could take a look at it. After harassing him bi-weekly about 6 months later, I finally got it back. A full year later last week. He told me there was a problem with the clutch assembly and he couldn’t fix it.
This week, I decided I would see if I could fix it. I opened it up and discovered he had cleaned the gummy tar from the old belts and replaced the two smaller belts, but the main belt was missing. Out came my belt kit and I installed the new belt. All was good for the first tape, my test tape. So then I put on Led Zeppelin 1 and started playing it. Played the first side well, although playback speed was slow. Second side, it ate the tape. Put back the test tape, and I tried to eat it too! And the rewind and fast forward were really poor. Open it back up and studied the mechanism. Removed the clutch, and saw a black gummy thing at the end of the pulley coming off of the secondary motor. A blob of degraded rubber turned to gum. I removed the blob and cleaned the shaft of the pulley with alcohol. The clutch gets its power from the gummy blob. What to use to replace it? I remembered how I repaired the automatic functions on a dual 621 when the Steuer-Pimpel had had the same issue. I cut the dry end of a pen refill and that worked. So I thought, why not try the same thing here!
I did that, and without going into all the drama I went through trying to put that damn c clip back on the clutch assembly, and the drama when I lost it, and the drama from losing the replacement c clip from an NAD donor deck, it is back and working well.
Only two problems left.
1) the deck plays well, but when it reaches the end, it automatically rewinds and starts playing again.
2) second and biggest problem, the playback runs slow. I tried adjusting the playback speed on the main motor, but it won’t turn enough, and I don’t want to force it and damage the pot inside. I’ve looked at the schematic, and it’s appears there’s no coarse adjustment. The transistor is turned on directly from the control ic.
Any ideas on either or both of these problems?
This week, I decided I would see if I could fix it. I opened it up and discovered he had cleaned the gummy tar from the old belts and replaced the two smaller belts, but the main belt was missing. Out came my belt kit and I installed the new belt. All was good for the first tape, my test tape. So then I put on Led Zeppelin 1 and started playing it. Played the first side well, although playback speed was slow. Second side, it ate the tape. Put back the test tape, and I tried to eat it too! And the rewind and fast forward were really poor. Open it back up and studied the mechanism. Removed the clutch, and saw a black gummy thing at the end of the pulley coming off of the secondary motor. A blob of degraded rubber turned to gum. I removed the blob and cleaned the shaft of the pulley with alcohol. The clutch gets its power from the gummy blob. What to use to replace it? I remembered how I repaired the automatic functions on a dual 621 when the Steuer-Pimpel had had the same issue. I cut the dry end of a pen refill and that worked. So I thought, why not try the same thing here!
I did that, and without going into all the drama I went through trying to put that damn c clip back on the clutch assembly, and the drama when I lost it, and the drama from losing the replacement c clip from an NAD donor deck, it is back and working well.
Only two problems left.
1) the deck plays well, but when it reaches the end, it automatically rewinds and starts playing again.
2) second and biggest problem, the playback runs slow. I tried adjusting the playback speed on the main motor, but it won’t turn enough, and I don’t want to force it and damage the pot inside. I’ve looked at the schematic, and it’s appears there’s no coarse adjustment. The transistor is turned on directly from the control ic.
Any ideas on either or both of these problems?
