Pioneer 701 Slow Running

Hi Steve,

we are now in the no mans land between the 701 and the 707. As yet I have never seen the circuit for a 701. I know that it will be similar but what the differences are......

First things first. In the photo of the machine internals, the PCB which is on the LHS of the photo has a relay on it. This should be the Rec Relay and should change state when the machine is recording. This should visibly change state and the associated click should be audible. When stop is pressed the relay should drop out after a short delay.

Is there any action?

GPS16
Thanks so much for your help! Its very hard to hear a relay as the whole pinch/tension assembly snap upward when I hit rec+play buttons. I'm going to pull the case and see if I can find that relay.
 
Hi Steve,

to check the operation of the relay. With no tape loaded, put the machine into Play. Hold the Pay button in. After around 1.5 to 2 secs, the loop for the Auto Stop should have dropped and a pronounced click should be heard. The Auto Stop will now have been over ridden and the machine should continue running in Play when the Play button is no longer depressed. Put the machine into pause. Now press the play button and the stop button at the same time and hold them. The Rec button will now be able to be pressed with the other hand and released. With the Rec button in, the relay should pull in and there will be no other activity to confuse the issue. When the Rec button is released, the relay should drop out again but after a short delay (around 2 secs).

The Relay is held in by a capacitor which discharges after a short time. The Bias Oscillator decays exponentially when turned off to simulate the gradual movement away of a Demagnetiser. The Record Relay needs to be held on for this duration to ensure that the Rec/Erase Heads do not end up with any residual magnetism by being isolated too soon.

See how this goes.

GPS16
 
Hi Steve,

to check the operation of the relay. With no tape loaded, put the machine into Play. Hold the Pay button in. After around 1.5 to 2 secs, the loop for the Auto Stop should have dropped and a pronounced click should be heard. The Auto Stop will now have been over ridden and the machine should continue running in Play when the Play button is no longer depressed. Put the machine into pause. Now press the play button and the stop button at the same time and hold them. The Rec button will now be able to be pressed with the other hand and released. With the Rec button in, the relay should pull in and there will be no other activity to confuse the issue. When the Rec button is released, the relay should drop out again but after a short delay (around 2 secs).

The Relay is held in by a capacitor which discharges after a short time. The Bias Oscillator decays exponentially when turned off to simulate the gradual movement away of a Demagnetiser. The Record Relay needs to be held on for this duration to ensure that the Rec/Erase Heads do not end up with any residual magnetism by being isolated too soon.

See how this goes.

GPS16
Thanks for your help and expertise. I apologize for not responding sooner. I just switched hospitals and am orienting to the emergency room (I'm an RN) and my life has been filled with more 12 hour shifts then usual.

I followed the procedure you laid out for me. An interesting note, with no tape loaded, hitting play makes the deck go into a fast forward mode, not a slower normal play speed (the tape speed button does change anything either...just keeps going fast)...if that makes any difference.
So when I release the rec button, I hear an immediate click, no 2 sec delay.

Thanks again for your help!
 
Thanks for your help and expertise. I apologize for not responding sooner. I just switched hospitals and am orienting to the emergency room (I'm an RN) and my life has been filled with more 12 hour shifts then usual.

I followed the procedure you laid out for me. An interesting note, with no tape loaded, hitting play makes the deck go into a fast forward mode, not a slower normal play speed (the tape speed button does change anything either...just keeps going fast)...if that makes any difference.
So when I release the rec button, I hear an immediate click, no 2 sec delay.

Thanks again for your help!
So I have tried the Tape 1 inputs and Tape 2 inputs on my Spec 1 preamp to make sure itwasntan issue with my preamp. I was very careful how my interconnects are connected as per the manuals on both the preamp and tape player. While recording, I don't get any comparison play back if I engage the "tape" button toggling back and forth between the "source" and "tape" buttons on the RT701...I've tried this with the monitor switch on my preamp set to both source and tape monitor positions and the "tape" button is dead...needles flat even with the line input knob mixed. I can adjust the line input knob properly when the Rt701 is set to source.

Well, this might be promising, I can hear very faint playback from one of my recordings...almost sounds like bleed over from another channel...very faint and I have to crank the preamp to hear it. I switch the tapes to a prerecorded tape and hear play back just fine....argh!
 
Hi Steve,

with no tape loaded the motors will spin fast but the torque in them will be much reduced. The speed of empty reel table will not be seen to change when the sped button is changed state. This changes the speed of the capstan shaft only. The operation of the record relay must be verified. The machine will never record unless it is pulled in. In your photo ending in 1230, the relay can be seen just to the right of the mains transformer. Instead of listening for it's operation, there should be mechanical movement seen through the relay's plastic cover. Try the same test again but visually.

GPS16
 
Hi Steve,

with no tape loaded the motors will spin fast but the torque in them will be much reduced. The speed of empty reel table will not be seen to change when the sped button is changed state. This changes the speed of the capstan shaft only. The operation of the record relay must be verified. The machine will never record unless it is pulled in. In your photo ending in 1230, the relay can be seen just to the right of the mains transformer. Instead of listening for it's operation, there should be mechanical movement seen through the relay's plastic cover. Try the same test again but visually.

GPS16


Yes. It clicks and I see that top plate in the relay click over to make contact.
 
Yes. It clicks and I see that top plate in the relay click over to make contact.

I do see 2 relays. Its the smaller relay near the back (across from the power transformer) that is making contact when I hit the rec button. There's a larger relay (about twice the size of the smaller relay) more near the front that doesn't seem to be doing anything.
 
Hi Steve,

The large relay near the front should change state when play is pressed. It should drop the power to the motors with a lower tap on the transformer and the big green resistor to set up the torques.

If the small relay changes state with the Record Button, verify that there is a delay before the relay drops out after stop has been pressed. This is important to stop magnetisation of the heads.

The next test is to find a recording that you don't mind erasing. Do a test recording over it and see if it is erased. If the machine erases tapes then the Bias Oscillator is running and we will then be a step forward.

Cheers.

Alyn B
 
Hi Steve,

The large relay near the front should change state when play is pressed. It should drop the power to the motors with a lower tap on the transformer and the big green resistor to set up the torques.

If the small relay changes state with the Record Button, verify that there is a delay before the relay drops out after stop has been pressed. This is important to stop magnetisation of the heads.

The next test is to find a recording that you don't mind erasing. Do a test recording over it and see if it is erased. If the machine erases tapes then the Bias Oscillator is running and we will then be a step forward.

Cheers.

Alyn B

Alyn-

I cleaned the line in and line out RCA jacks last night and wiggled the RCA cables to see if I could see a deflections on the needles when recording. The needles were dead flat when the "Tape" was on, hit the button for source and everything was fine and sounded great. I could adjust the line levels fine. So I put it in "Tape" again and its recording!!!!! The levels have dropped, but its recording! The right channel is way lower than the left channel so I adjust the right line level to boast it up to match the left side and get it to come close, but every once in a while it goes max into the red, then drops back down. Left channels sounds ok, not great, but much better than the right channel.

When I hit "Stop" to get out of recording, there is no delay at all; it immediately stops.

I wonder if the caps on the line level board are shot?

Thanks SO much for your help. Where do I go from here?

-Steve
 
Alyn-

I cleaned the line in and line out RCA jacks last night and wiggled the RCA cables to see if I could see a deflections on the needles when recording. The needles were dead flat when the "Tape" was on, hit the button for source and everything was fine and sounded great. I could adjust the line levels fine. So I put it in "Tape" again and its recording!!!!! The levels have dropped, but its recording! The right channel is way lower than the left channel so I adjust the right line level to boast it up to match the left side and get it to come close, but every once in a while it goes max into the red, then drops back down. Left channels sounds ok, not great, but much better than the right channel.

When I hit "Stop" to get out of recording, there is no delay at all; it immediately stops.

I wonder if the caps on the line level board are shot?

Thanks SO much for your help. Where do I go from here?

-Steve
I should probably let you know that I thoroughly cleaned all the top buttons with deoxit and cycled them about 100 times each. These are the In/Off, Speed, Tape&Source, Bias & Eq buttons.

-Steve
 
Hi Steve,

When recording, the machine will stop as soon as the stop button is pressed. The record relay should stay in for a short delay. The relay should hold in for 1.5 to 2 secs. I know that there is a lot going on when the stop button is pressed. But as mentioned previously minimise it by putting the machine in pause. Hold the play button in. with the other hand press record. The rec relay should pull in. Whilst still holding in the Play button, press the Stop. The Rec button should pop out and the relay should then be heard to drop out after the delay. The changes in levels could well be due to the relay in question as the switches look to have been dealt with.

This relay is the "man of the match" at the moment. Until this is deemed to be functional, any further checks will not hold much meaning. If this relay is NOT OK then any tapes recorded and played are at risk of partial erasure due to residual magnetisation that the delay is supposed to inhibit.

Keep trying and ask further questions if what I am asking you to do is not clear. The delay to drop out is important.

Keep going.

GPS16
 
Hi Steve,

When recording, the machine will stop as soon as the stop button is pressed. The record relay should stay in for a short delay. The relay should hold in for 1.5 to 2 secs. I know that there is a lot going on when the stop button is pressed. But as mentioned previously minimise it by putting the machine in pause. Hold the play button in. with the other hand press record. The rec relay should pull in. Whilst still holding in the Play button, press the Stop. The Rec button should pop out and the relay should then be heard to drop out after the delay. The changes in levels could well be due to the relay in question as the switches look to have been dealt with.

This relay is the "man of the match" at the moment. Until this is deemed to be functional, any further checks will not hold much meaning. If this relay is NOT OK then any tapes recorded and played are at risk of partial erasure due to residual magnetisation that the delay is supposed to inhibit.

Keep trying and ask further questions if what I am asking you to do is not clear. The delay to drop out is important.

Keep going.

GPS16

I'm off to a 12 hour night shift, but I'll give this a go tomorrow morning. Thanks again, I really appreciate all your help.
 
Hi Steve,

When recording, the machine will stop as soon as the stop button is pressed. The record relay should stay in for a short delay. The relay should hold in for 1.5 to 2 secs. I know that there is a lot going on when the stop button is pressed. But as mentioned previously minimise it by putting the machine in pause. Hold the play button in. with the other hand press record. The rec relay should pull in. Whilst still holding in the Play button, press the Stop. The Rec button should pop out and the relay should then be heard to drop out after the delay. The changes in levels could well be due to the relay in question as the switches look to have been dealt with.

This relay is the "man of the match" at the moment. Until this is deemed to be functional, any further checks will not hold much meaning. If this relay is NOT OK then any tapes recorded and played are at risk of partial erasure due to residual magnetisation that the delay is supposed to inhibit.

Keep trying and ask further questions if what I am asking you to do is not clear. The delay to drop out is important.

Keep going.

GPS16

Ok, while paused, I press play+rec buttons and see the relay close. I keep holding play and hit stop and start my count. If saying "one one thousand" "two one thousand" etc., to count off the seconds, the relay opens after I say "one". Which is a fraction of a second. My guess is that the relay opens at about 1/3rd of a sec...no where near 1.2 to 2.0 secs. Although there is a perceptible delay, it is slight.

-Steve
 
Hi steve,

you have a delay. Not as long as I would like but you have a delay. There is an Electrolytic Capacitor across the winding of the relay. On a 707 it is 100uF/35V. This may need replacing. As the 701 uses a different relay, the value may be different.

Could you look at the PCB on the LHS of the machine. This should be the Power Supply and Solenoid Control. There should be a number on the PCB, if it is a RWG-070 then it is the same as the 707. There is a capacitor on this PCB which acts as a timer which reduces the voltage to the solenoids when they have pulled in. This cap is very important as well, it is 22uF/35V on a 707. The solenoids can be cooked if this cap fails.

If you can find the number on the PSU board, we can then take things from there. Due to the age of the machine a few Electrolytic replacements may be beneficial long term. Due you have any Soldering Skills?

GPS16
 
Hi steve,

you have a delay. Not as long as I would like but you have a delay. There is an Electrolytic Capacitor across the winding of the relay. On a 707 it is 100uF/35V. This may need replacing. As the 701 uses a different relay, the value may be different.

Could you look at the PCB on the LHS of the machine. This should be the Power Supply and Solenoid Control. There should be a number on the PCB, if it is a RWG-070 then it is the same as the 707. There is a capacitor on this PCB which acts as a timer which reduces the voltage to the solenoids when they have pulled in. This cap is very important as well, it is 22uF/35V on a 707. The solenoids can be cooked if this cap fails.

If you can find the number on the PSU board, we can then take things from there. Due to the age of the machine a few Electrolytic replacements may be beneficial long term. Due you have any Soldering Skills?

GPS16

Yes on the soldiering skills; amps, guitar pedals, and just recently recapped my hybrid (tube/ss) Kenwood HAM radio. I don't have some of the diagnostic equipment I wish I had, just a fluke multimeter.

I'll see if I can find those caps and then get back to you. If I have caps in those values I'll swap them out and see what gives.

-Steve
 
Hi Steve,

if you are OK soldering then On the PCB with the record relay on it replace the large Electrolytics. On the Solenoid Control PCB replace the large caps on there as well. That will give both the Analogue and the Solenoid power supplies a bit of a spruce up and the 2 smaller caps will help the Record Off delay and keep the solenoids cool.

If you have a Fluke Multimeter then the rec delay cap should be found easily by continuity checks around the coil of the relay.

Keep us posted.

GPS16
 
Yes on the soldiering skills; amps, guitar pedals, and just recently recapped my hybrid (tube/ss) Kenwood HAM radio. I don't have some of the diagnostic equipment I wish I had, just a fluke multimeter.

I'll see if I can find those caps and then get back to you. If I have caps in those values I'll swap them out and see what gives.

-Steve
Hi Steve,

if you are OK soldering then On the PCB with the record relay on it replace the large Electrolytics. On the Solenoid Control PCB replace the large caps on there as well. That will give both the Analogue and the Solenoid power supplies a bit of a spruce up and the 2 smaller caps will help the Record Off delay and keep the solenoids cool.

If you have a Fluke Multimeter then the rec delay cap should be found easily by continuity checks around the coil of the relay.

Keep us posted.

GPS16

I found a 100uf 35v cap snuggled right against the relay to the left of relay, its the only 100uf 35v cap on the board. Not sure if I have to remove the cap before I can measure it accurately. Also, if you see the 2 resistors just above and to the right of the relay, on the back of the pcb I noticed gray residue that looked like something got smoked. I wish I would have taken a pic before I wiped it clean...looks like something arced there. The resistors look fine though. I see 2 labels on the board, in big letters there is a KYJ, and in smaller letters I see RWR 059.
 

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Hi Steve,

if you are OK soldering then On the PCB with the record relay on it replace the large Electrolytics. On the Solenoid Control PCB replace the large caps on there as well. That will give both the Analogue and the Solenoid power supplies a bit of a spruce up and the 2 smaller caps will help the Record Off delay and keep the solenoids cool.

If you have a Fluke Multimeter then the rec delay cap should be found easily by continuity checks around the coil of the relay.

Keep us posted.

GPS16

On the board to the left (below the relay board in the picture I just attached) I see RWF-081. I'll play around with the continuity check until I find the right culprit.

Access is great on the boards and the traces look pretty heavy duty. This should be easy. I wonder if I should order all the caps (maybe someone has a Mouser BOM on this) and take this board by board. I wonder how long it will be before that other play relay gives me fits?
 

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On the board to the left (below the relay board in the picture I just attached) I see RWF-081. I'll play around with the continuity check until I find the right culprit.

Access is great on the boards and the traces look pretty heavy duty. This should be easy. I wonder if I should order all the caps (maybe someone has a Mouser BOM on this) and take this board by board. I wonder how long it will be before that other play relay gives me fits?
 

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Hi Steve,

if you are OK soldering then On the PCB with the record relay on it replace the large Electrolytics. On the Solenoid Control PCB replace the large caps on there as well. That will give both the Analogue and the Solenoid power supplies a bit of a spruce up and the 2 smaller caps will help the Record Off delay and keep the solenoids cool.

If you have a Fluke Multimeter then the rec delay cap should be found easily by continuity checks around the coil of the relay.

Keep us posted.

GPS16

Ok, I have a supplemental service manual (unfortunately not the main manual) RWR 059 is the "Power oscillation assembly" board, and RWF 081 is the "Playback amplification assembly"
 
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