Pioneer Rt-707 Recording

Wilcocat

Wilcocat

New Member
I recently acquired a 707. I have read most of the threads relating to this machine. Thanks to everyone who have posted. The unit plays great. I get a good signal to source. While recording with proper source level if I switch from source to tape there is no signal. If I increase the line level there is a very distorted single that will record. If I record with no input source it does erase the tape. After reading I have done the following:

Cleaned the heads
Cleaned all switches several times using CRC contact cleaner

I cannot repair the unit myself.

I have a local tech that will attempt the repairs if I can point him to the possible issue(s). I have located the service manual.

Any advise on where to start would be greatly appreciated.
 
You say the unit plays great but when you switch from source to tape there's no signal? I'm assuming that you mean that pre-recorded tapes play well? I further assume that when you are attempting to record, the incoming signal sounds fine while your listening to source? But when you switch to tape there's basically nothing? And your sure that you have the machine in record mode? Record mode buttons (top row RH side) on (pressed in) for both channels? Red light between the meters comes on when you press play and record together? If all of that is done and nothing records, then there is something wrong that will likely take a tech to trace down. GPS16 here on AK could probably walk you through the repair - if your willing to try?
 
soundmig said:
You say the unit plays great but when you switch from source to tape there's no signal? I'm assuming that you mean that pre-recorded tapes play well? I further assume that when you are attempting to record, the incoming signal sounds fine while your listening to source? But when you switch to tape there's basically nothing? And your sure that you have the machine in record mode? Record mode buttons (top row RH side) on (pressed in) for both channels? Red light between the meters comes on when you press play and record together? If all of that is done and nothing records, then there is something wrong that will likely take a tech to trace down. GPS16 here on AK could probably walk you through the repair - if your willing to try?
Click to expand...
Everything you mentioned is correct. I would really like to get this machine repaired. Maybe start with the most likely culprit. Thanks for the reply.
 
Hi Wilcocat,

If the unit is erasing OK then the Bias Oscillator is running OK. The Record side goes through a relay, one relay for each channel. The operation of these relays needs to be verified. The relays are the type which exhibit a decent click when operated so it is not too difficult to check the mechanical operation.

With no tape loaded (not necessary for this test). Press the Pause Button in. This will stop clunks and motors driving so you can listen to the relays. Then press the Rec and Play buttons together. This will prepare the machine for recording. If no Rec Mode buttons are pressed in, then the Red LED in between the VU Meters will not be lit. Select each one in turn. On each press in, the relay should be heard to click in. When the button is released, the relay should be heard to drop out after a delay (about 1.5 secs ish). If these clicks are not heard then the machine will never record as the audio record signal will be shorted out to ground. If the clicks are present and correct then there will be an electrical issue which needs attention.

Are there any indications as to how the machine has been stored? Are there signs of corrosion present? If there is, this does not do relay contacts any good at all. Also as an assist, with the machine powered off move ALL the switches to and from both states. It will help the contact clean up operation. The REC button (next to the play button) is an important one. There are contacts on this which form "Interlocks". If they have bad connections there are very odd faults which can arise.

First things first. See how this check goes and we will take things from there. We need to hear a quick click in and a slow click out for both Rec Relays which are set by the upper mode buttons.

Cheers.

GPS16
 
GPS16 said:
Hi Wilcocat,

If the unit is erasing OK then the Bias Oscillator is running OK. The Record side goes through a relay, one relay for each channel. The operation of these relays needs to be verified. The relays are the type which exhibit a decent click when operated so it is not too difficult to check the mechanical operation.

With no tape loaded (not necessary for this test). Press the Pause Button in. This will stop clunks and motors driving so you can listen to the relays. Then press the Rec and Play buttons together. This will prepare the machine for recording. If no Rec Mode buttons are pressed in, then the Red LED in between the VU Meters will not be lit. Select each one in turn. On each press in, the relay should be heard to click in. When the button is released, the relay should be heard to drop out after a delay (about 1.5 secs ish). If these clicks are not heard then the machine will never record as the audio record signal will be shorted out to ground. If the clicks are present and correct then there will be an electrical issue which needs attention.

Are there any indications as to how the machine has been stored? Are there signs of corrosion present? If there is, this does not do relay contacts any good at all. Also as an assist, with the machine powered off move ALL the switches to and from both states. It will help the contact clean up operation. The REC button (next to the play button) is an important one. There are contacts on this which form "Interlocks". If they have bad connections there are very odd faults which can arise.

First things first. See how this check goes and we will take things from there. We need to hear a quick click in and a slow click out for both Rec Relays which are set by the upper mode buttons.

Cheers.

GPS16
Click to expand...
Thanks for the reply. The clicks are present as you described.
The unit was being stored inside a heated and cooled room when I bought it. I'm not sure of the entire storage history. The machine was very dusty inside. There is some corrosion from the thin strip between the top cover and chassis. This has transferred to the underside of the top cover. Other than the dust the unit appears clean.
I have attempted to clean the switches by spraying contact cleaner in the small holes on top or each. I then worked the switches numerous times.
 
Hi Wilcocat,

"Welcome to the Reel World Neo", as I have said in other threads

The relays are operating as they should by the sound of it!! (Literally) The next step is to find something that is common to both channels. You have not said anywhere that only one channel is faulty so I am assuming that the problem is on both channels. Is that correct?

Are you in possession of and can you operate a Multimeter?

If not can you get hold of one?

As you state you have a manual, the first "Common" point to check is the operation of S2-1. If you have the diagram 13.4 on page 64 (in the manual I have), look in square A4. The centre of S2-1 is on the 30V from the power supply. Either side of S2-1 then selects which section of the following switch (S5) picks the correct Equalisation setting for Std-LH, the speed being picked by S2-1. Pairs of transistors (Q1201-8), then select the equalisation networks in the Eq Amp.

If you have a manual and a Multimeter this can be checked with the Unit powered off and the Meter set to continuity and connected to pins on the PCB at the top with all the switches on.

GPS16
 
GPS16 said:
Hi Wilcocat,

"Welcome to the Reel World Neo", as I have said in other threads

The relays are operating as they should by the sound of it!! (Literally) The next step is to find something that is common to both channels. You have not said anywhere that only one channel is faulty so I am assuming that the problem is on both channels. Is that correct?

Are you in possession of and can you operate a Multimeter?

If not can you get hold of one?

As you state you have a manual, the first "Common" point to check is the operation of S2-1. If you have the diagram 13.4 on page 64 (in the manual I have), look in square A4. The centre of S2-1 is on the 30V from the power supply. Either side of S2-1 then selects which section of the following switch (S5) picks the correct Equalisation setting for Std-LH, the speed being picked by S2-1. Pairs of transistors (Q1201-8), then select the equalisation networks in the Eq Amp.

If you have a manual and a Multimeter this can be checked with the Unit powered off and the Meter set to continuity and connected to pins on the PCB at the top with all the switches on.

GPS16
Click to expand...
Thank you sir. Unfortunately I cannot operate a multimeter. I will pass this information to the repair tech and go from there. It will not take long to overspend on repairs so my attempt to join the ranks may be futile. I appreciate your help.
 
Your Welcome!!!

What AK is for.

Hope the problem is sorted soon. You have just acquired a gem of a machine which will astound when it is running!!!

Cheers.

GPS16
 
Greetings from his tech. There were bad transistors in the record circuit. a broken leg on a resistor in the headphone circuit. Of course the counter belt needed to be changed, the counter was gummed up. and the auto stop was gummed up and not dropping the switch mech far enough to shut off.
It is a sweet sounding machine. I may not give it back haha. I think he will be happy playing with his deck.
 
Hi Charlietrain,,

so glad you sorted out Wilcocat's machine. They are fine machines indeed.

Cheers.

GPS16
 
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