RT-707 - Won't play / controls unresponsive, any ideas?

Discussion in 'Pioneer Audio' started by notropey, Oct 30, 2017.

  1. notropey

    notropey New Member

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    Hi Guys, appreciate any help. I have a RT-707, it turns on, VU's light up, capstan motor is running however the controls for playing won't engage. The direction lights won't light up, either will pause and the bulbs are good in both. This is the variant that doesn't have the fuses underneath, so its not a fuse. Anyone got an idea what it might be. There is no relay click when power is engaged and the capstan motor doesn't sound right, but forward and rewind work. Any ideas? Thanks
     
  2. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Try it with a tape threaded thru the tape path this time.
     
  3. notropey

    notropey New Member

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    It has tape on it.
     
  4. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    And you have it threaded correctly per the manual??
    ScreenHunter_144 Oct. 30 09.24.jpg

    With the capstan motor not sounding right by your own admission, I would think it needs a fair amount of work, lubricating, circuit tracing, etc. Download the Service and owners manuals here if you haven't already.
     
    Last edited: Oct 30, 2017
  5. notropey

    notropey New Member

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    Its not a threading issues or anything so simple, I have 3 of theses machines. The circuit that engages the play mechanism is not getting power.
     
  6. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Circuit descriptions (electrical) are described on page 10 thru 20 in the manual. Play Circuit is on page 10. You'll need at least a multimeter to check voltages at the various components in the description. Do a complete cleaning and lube of the capstan motor, and other bearing's/bushing's 1st so the circuit loads aren't exagerated upon start up. You may end up replacing a few transistors and capacitors. Look for bloated or open caps, burn't and or broken resistors, and other signs of abuse 1st after cleaning.
     
  7. notropey

    notropey New Member

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    Yep thats what I've been doing. Unfortunately the service manual out there is for the US 120v fused variant, and this is the International multi-voltage non fused variant, the circuits are revised. As this is such a common deck I was hoping someone out there had encounter this issue before.
     
  8. audiojones

    audiojones Jonesin' for audio Subscriber

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    Don't know if it'll help but I've run into a similar issue in an RT-707 before. IIRC I had a failed zener diode ZD-401 and transistor Q401 in the power supply which took out the regulated 32V control voltage rail and caused the same symptoms you are describing. Take a look at the schematic and check for presence of 32 volts supplying the control voltage rail, sounds like you may have a PS problem. Make sure there are no short circuits or funky wiring issues with the forward / reverse indicator lights or other circuits running off of the control voltage rail as a short here will cause trouble downstream in the PS.
     
  9. notropey

    notropey New Member

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    Thank you, that helps a lot. On my variant the circuit doesn't have Q401 only Q402, but yes I suspect that ZD-401 has failed. So I'll check the voltages tonight, and the wiring, hopefully order some parts and be back in business. Thanks again.
     
  10. kfalls

    kfalls Well-Known Member

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    I had a similar problem with a Revox B77. There was an on-board Zener diode and transistor which made up the 5V power supply for the logic circuits. Everything else worked. I replaced the Zener and was back in business.
     
  11. larryderouin

    larryderouin Do I get Food, Med's, or more gear this Month? Subscriber

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    Is this the only int'l multi voltage unit you have or do you have another multi voltage unit to compare it with?
     
  12. notropey

    notropey New Member

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    Sorry for the delay. There was success, after a lot of probing of this deck and and a working one, I discovered that Q402, ZD401, Q308 & ZD301 had all gone. Giving me a deck with no output or controls. Anyway replaced all of those, now it works.

    However the deck seems to have a pitch issue, playing too fast. I should mention that this was a parts machine that I am resurrecting and it never worked and the previous owner had butchered it. So this is the first time I've actually heard it play.

    So now attempting to fix this issue. So I replaced the caps on the RWG-076 - but not C901 as don't have a replacement yet. The pitch pot and speed switch have been cleaned as has the molex connector and the pins for the board it attaches to.

    I can adjust the pitch pot to the lowest setting and this speed sounds kinda ok, does seem like too much wow and flutter. Oh and I have replaced the pinch roller too. Kinda outta ideas.

    Any ideas what else I may have overlooked?
     
  13. notropey

    notropey New Member

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    FYI there are some adjustment pots on RWG-076, that were outta wack. Adjusted them and that sorted out the pitch issue.
     
  14. audiojones

    audiojones Jonesin' for audio Subscriber

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    Don't know if it's the same problem you are experiencing however I've run into speed issues with these machines in the past that turned out to be dirty contacts on reversing relay R901. The usual cleaning of the speed pot and Molex connector did nothing, however tapping on the reversing relay housing resulted in correct operation. I have cleaned the relay contacts in the past with good results but it's probably best to replace it if this turns out to be your problem.

    If it is bad and you are going to order a new relay also check your recording osc. relays. Run a line signal into the input of the deck and load a fresh blank tape on the machine. Turn the record volume up all the way and push play (NOT record) and listen to the tape play back as it rolls without record being engaged. If you hear a garbly signal being laid down on the tape then replace both record osc. relays because the contacts have oxidized and are not grounding out the incoming signal properly which allows it to get to the record head.

    This can of course ruin your recordings if you are playing tapes on the machine while a signal from another source is still present at the record input jacks (as it would likely be with any receiver or amp with a tape monitor loop) and your record volume is not set to zero. Of the many RT-707 and 701 decks to come through here over the years I've only come across one or two that didn't do this, and I don't think anyone really checks for this problem (at least no one ever seems to bring it up). Good thing to check for if you don't want to lay a garbled signal down on your pre recorded tapes.
     
  15. notropey

    notropey New Member

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    Thanks, the reverse relay seems to be fine. And thanks for the advice on the recording relays. On detailed inspection of the head block I have found a big issue which would affect the wow and flutter. It seems the previous owner has completely removed one of tape guide posts on head block, the one next to the record head in the middle of the block. Add to that they removed the one next to the forward play head and just glued it back in, wow I'm just surprised at this hack job. So I have removed the glue and screwed it back in, and I managed to find someone selling the middle post. Add to that I'm positive the head alignment has been played with by the pervious owner, thats gonna be fun to fix. Gotta wait for the parts first.

    Also another thing the previous owner did to get around the original issue of the deck not producing any sound was to drill holes through the back and directly solder rca cables to the forward head only, then hooked this up to a Shure Pre-Amp then into an amp. And they were selling as a superbly playing deck, hah. So all their hackery is slowly being undone. Glad I only got this as a parts machine. But there is life still in it and its slowly coming back to the way Pioneer intended.
     
  16. audiojones

    audiojones Jonesin' for audio Subscriber

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    Sheesh, this deck sounds similar to a hacked up RT-707 I bought years ago from an unscrupulous seller on CL. It had the reverse head cut out, components cut out from the servo circuit board and wires tied in where the components were, tape guides removed, an extra set of jacks hacked into the back, a hole drilled into the faceplate with a switch in it and a wire with bare ends hanging from a hole that was cut into the top of cabinet.

    Of course the CL ad said "RT-707 in good shape" and the picture was a fuzzy thumbnail size photo so you couldn't see how hacked up it was. It was a decent price so I foolishly drove an hour to get it and boy was I surprised (pissed) when I saw it. The seller told me that this was a common mod done by DJ's to make it work as a variable speed echo / time delay unit for some kind of trance / disco / club music or something. I guess they don't know about the tons of cheap digital echoplex style units out there or maybe this mod predates all of that stuff (though I don't think it was done all that long ago). He said there used to be a website somewhere that told you you how to "modify" (ruin IMO) your RT-707 so you can mount it in the rack with your other DJ gear and have a variable speed tape echo device.

    Yeah, I bought the machine anyway of course and someday I'll get it working again if I can find all the parts that have been hacked out of it. At least the service data and schematics are readily available so I can see what's been cut out of the boards, but man what a waste of a nice machine!
     
    Last edited: Nov 9, 2017
  17. notropey

    notropey New Member

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    Wow, now that sounds like a real mess. That will be a challenge to put right.
     

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