I have a mint looking Pioneer rt-707 R2R busted it back out of the box, it plays back perfect both channels with older recoreded tapes made with it, but new recordings the left channel makes alot of noise rumbling and hissing right channel comes out perfect,when recording,the monitor switch is on source both channels i can hear with the tape monitor on my reciever, when i put the monitor switch on tape whilst recording the thing does nothing on the left channel just a bunch of noise, and on normal playback of newly recorded material and new maxell tape, i've cleaned out the switches, controls, cleaned and demagnatized the heads, and it still does it, any insight or suggestion would greatly be appreciated

I would try teh following to know if the recording head is busted or the problem lies elsewhere: Record something, monitor the TAPE, now, hold the tape away from the recording head (be VERY careful tho), if the rumbling noise persists, the problem isnt the head, if it stops, likely the head IS the source of the problem.

i tried that it didn't change anything, i thought about hitting it with a can of electronic non residue contact cleaner thats plastic safe by CRC anybody else have any suggestions?

Have you tried cleaning the switches ???

Have you tried cleaning the switches ???

That's the first place to check. If the meters move in source in both Record and Play, the Tape/Source switch is most likely the problem.

Ron

ive cleaned the push button switches, but there is switches that move with the carriage and some solenoids, i thought about dousing it with cleaner, just avoid motors and brakepads i think,anything else on mind, i really do appreciate the suggestions.

i cleaned everything with contact cleaner and cleaned the pots inside varible resistors and i think varible caps? (they have a ferrite core inside) i moved them all while cleaning and i noticed two of them where cracked inside and would barley turn so i left them alone,(if anybody knows the inside of this R2R recorder the ones that are on the board with the 2 white covered relays), now neither channel will record from the inputs mic, line and the din jack, just get a bunch of static when trying to record and the meters just move with the static and cracklin, plays what was recorded years ago fine, info would greatly be appreciated

i cleaned everything with contact cleaner and cleaned the pots inside varible resistors and i think varible caps? (they have a ferrite core inside) i moved them all while cleaning and i noticed two of them where cracked inside and would barley turn so i left them alone,(if anybody knows the inside of this R2R recorder the ones that are on the board with the 2 white covered relays), now neither channel will record from the inputs mic, line and the din jack, just get a bunch of static when trying to record and the meters just move with the static and cracklin, plays what was recorded years ago fine, info would greatly be appreciated
I hate to tell you this, but it sounds to me like you may have just made your problems much worse. :sigh: Never twist variable choke unless you know exaclty what you are doing! These are extremely fragile devices, and can crack easily, at which point they will not be tunable anylonger.

A choke will never cause the sort of problems that you are experiencing anyways, so these should be left alone unless you REALLY know your stuff. Cleaning pots is great, but be careful about what exactly you start twising, because one wrong twist on one of those ferrite core chokes can turn them into dust! :yes:

the chokes are bias traps and are not your problem.
the 707 has a relay that switches between play heads for the reverse mode, and the relay needs DeOxit. Look for the relay by following the shielded head wires back to the circuit boards. Drill a tiny hole in the relay's cover, squirt, and cover the hole with a dot of silicone.

i have the schematics somewere, i should have looked for it(got lazy i guess),i use them to fix the other peices of pioneer and sansui audio equipment i have, if i knew those were bias adjustments i would have left them alone, well ill try the relay for the reverse, thanks for the info, see what else i can fix or break lol

the chokes are bias traps and are not your problem.
the 707 has a relay that switches between play heads for the reverse mode, and the relay needs DeOxit. Look for the relay by following the shielded head wires back to the circuit boards. Drill a tiny hole in the relay's cover, squirt, and cover the hole with a dot of silicone.
The relay advice given here is excellent, and should be heeded. The odds are that this will probably cure your original problem. Although your bias traps are probably now shot.

If there is a recording and/or playback problem, I always press my finger against the backside of the tape to simulate a pressure pad such as was used for a few years on Sony reel-to-reels. (Wash your hands to get the oils off before doing this.)

I press the tape directly against the head. If the problem is the head, the recording and/or playback quality will immediately and obviously improve. If there is no improvement, then the cause of the problem is probably not the head.

* * * * *

Also, like Goldear says, messing with the adjustments (capacitors, inductors, resistors) usually makes problems worse. You can clean the variable resistors with Caig DeoxIT if you put them back exactly where they were, and messing with variable capacitors may be useful in setting the bias, but it's usually best to keep one's hands off the inductors. They are fragile as hell.

Hope this helps.

Fred Longworth
StereoTech Classic Audio Repair
http://www.repairaudio.com

Try this. Record over a know tape with material recorded on it. Turn the Line Level control to "0" and record over it. If the Bias oscillator is good, the tape will be erased. If not, it won't.

Ron

It erases with no static recorded when the record levels are on zero on a tape that has been previously recorded as of 04/04/2006, i tried the pressure pad idea also thanks though, but i haven't tore back into it to clean the relays, lots of work being a systems administrator, everything piles on at once