common defects found in Revox B-215?

[Mikemaxcel]

One of my H1（the latest model-1991）and a just arrived B215 （the earliest model-1985）both having the same defective behaviours.
On playbck, FF or FR, the mechanism automatically stops within seconds and the auto-tape type detection just got crazy and could not fixed on the tape type used.
I have no way to get them fixed.
If you could, please help me with your advice.http://img805.imageshack.us/img805/5868/revoxb215sensorflexboar.jpg
The problem might be faulty DL1-DL4 or QP1-QP4 on the Tape Transport/Sensor Flex Board.

[perry]

Those 2 issues are not related, AFAIK. The FF & REW issue is often a common problem due to gummed up or worn bearings in the reel motors. The motors have to be taken apart and cleaned & lubed. It can also be the small "cassette loaded" switch in the tape well. It is a small push in pin switch that if is dirty/defective will randomly stop the tape because it is detecting "no tape". The tape type issue is normally just dirty or bent contacts on the tape detection leaf switches in the upper area of the cassette well.
Normally, any B215 (and I assume H1) will benefit greatly from replacing the Frako and Philips electrolytic caps in the deck. They wreak all sorts of havoc as they fail.

[ke4mcl]

i have not worked on that machine but have found these problems on other brands of decks.

the tape type select i have found to be dirty switch contacts. the erratic changes in direction can be caused by dragging motors or transport. also some decks that use optical tape counters can act weird if the optical sensors are caked with dust.

[Tinman]

Perry nailed it. *bigthumbup*

Marc

[Mikemaxcel]

Strange enough，all the mentioned defects are solved and cured after I cleaned and polished the
switches （S-met，S-eq, S-ren, S-cass）and the induced hum is slso gone

[perry]

Good job! You didn't mention the hum. Glad it wasn't the motors! I should have mentioned that if the motors stop suddenly anywhere on the tape, even in the beginning, it is unlikely to be a motor problem, and is likely switches. If it stops suddenly during play (FF or REW) after the first half of the tape, (when torque is higher on the take-up) it is much more likely to be a motor issue. The Play, FF, and REW issue could also have been a defective leader detector, always indicating "leader".