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Servicing a SONY DAT machine (Pictorial)

No I didn't. I will, I recorded 400Hz sine wave on my other working Pioneer DAT (D-07A) to see if what is happening. Will post it soon.
 
So when the sound is fine (first few seconds of playback) the RF signal also looks fine to me, picture below.
But when it starts to drop out, it fluctuates, I made a film, link below:
 

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Didn't do it, will try later but I' not sure how to do it. There are two signals, one RF and another is a square wave.
 
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I don't know the model of your scope, but inverting the trigger (switching between rising or falling edge) will select either one or other head.
 
Hi all!

I bought recently a Panasonic SV-3700 for parts (as usual!)

I like it because of the white color but the transport is a piece of s$1t. Over complicated and with a dozen of plastic parts and gears.

Even the cheapest Sony transport is better than this in my opinion. Panasonic already eat 2 tapes on me while the 5 - 6 Sony that i have never eat a tape.

Anyway i disassembly everything, clean it very well and applied white grease as per technical guide manual. I also replace the 3x brake pads but in not sure about the correct thickness....

The problem that i have now is that a) some times the take up reel doesn't start, so the pinch roller takes the tape out from the supply reel and spill it into the mechanism.
This can happen in both directions (play or shuttle reverse play) or FF/REW.
The results is usually serious damage to the tape...

b) from play to stop or FF/REW to stop the tape is loosing its tension and can fall off the S1 and T1 guides and from the drum. I can see that the brakes are applied and the reels are not moving (so brake pads are probably ok?) and the slack is introduced on the pinch roller disengagement.

Is anyone with some experience on this transport able to help me?

Thanks!
 
Hi. I have a Sony PCM-7010 that suddenly went "dead". I can hear some winding sounds, maybe from the transport, but there is nothing on the display and no buttons are responding. This happened when i was in the menu looking for the digital input menu. It is also like this after unplugging power from it. Anyone know what could cause that...?
 
Hi

My first guess would be the power unit which is split in several boards.

Especially check the switching regulator board (vertical board at the back of the cabinet).

Be aware that this model is particularly complex.
 
Got it to work by holding menu button when powering on. But the problem is that i cant get the digital inputs to work. And i cant find the menu to activate/deactivate them. So seems like it does not recognice the digital boards... And i cant find the digital input option in the menu.
 
Hi,
I got a "non-working" Sony DTC690 with a clearly loose (too loose) timing belt. Searched web for the item without success. The few places that showed up are "out of stock".
Any clues on wher to find it ??

part details:
Sony
Part Number: 3-368-417-01
Description: Belt (170Tn10-1.0t) Timing
Used in: DTC-59ES, DTC-60ES, DTC-670, DTC-690, DTC-790, DTC-A7, DTC-P7, DTC-ZE700, DTCA6, PCM2300, PCMR300

Thanks in advance !!
 
Hi all, I have a Sony A8 with an issue: no audio when i hit Play (and meters indicate no sound). Strangely, if i quickly hit and release FFW it kind of 'jolts' the audio back to life. Not dissimilar to when you have an amp with a dirty source selector and you wiggle it get sound in both channels. However, after a few minutes the audio starts to distort and drop out even if i get it to start using the the FFW trick. I was hoping a recap of the RF amp board would sort it out: however I completed that yesterday and it has not.

From other similar (if not quite the same) issues i've seen discussed here and elsewhere my next point of investigation will be the solder joints from the drum head cable> RF amp board > main board.

Any other thoughts?

The unit works flawlessly with a tape out if i just use the A/D or D/A converters. In this scenario i notice the relay makes two quiet clicks when an analogue or digital audio input is fed in. With a tape, however, i hear only one click when i initiate playback. This is to say: I think the mainboards, including relay, are fine --- the issue seems to lie somewhere in the RF amp signal not properly arriving into the mainboard? Appreciate any thoughts. I will also mess around with it today and see if i can make progress!
 
Hi

I can see 2 options here :
- dirty heads
- old grease jamming the guides

Remove the cover and, while playing, check that the 2 guides that wrap the tape around the drum are firmly held in their end-catcher, especially the left one.
 
thanks for your quick and tireless attention to these DAT troubles, hdrobien! I have never worked on this mechanism, so can you confirm you are talking about the items highlighted: ?


Screenshot 2024-10-29 091055.png
 
Yes, the guides are parts #211/206/205/203 and the end-catchers are parts #207. Don't touch parts #202/203.

All transports of that kind I have serviced were suffering from hardened grease preventing the left guide to firmly lock in its catcher, thus bad tracking / heads contact.

Another issue to check, in some cases, the guide post (#203) becomes loose in its socket (#211). You have to re-grimp it.
 
update so far: if i get the deck to produce DAT tape audio by hitting FFW quickly AND it arrives at the point where it starts to distort -- if at that point i lightly press on the end of post 203 it makes the distortion go away. So it seems there is a problem there. Any thoughts on a quick and safe way to lubricate? or should i suspect a loose post as you note above?

That being said, whatever i touch in the mechanism does not trigger audio output when pressing PLAY. Tape is turning but there doesn't seem to be anyway to induce audio unless i quickly tap FFW on and off.

I also see that on of the blue rollers doesn't seem to turn. lower one on left hand side. However, even in a condition where deck produces audio (if i do the FFW trick) there is no change to this or anywhere else in mechanism -- at least that i can see.
 
If you are talking about the LEFT post, this is a typical issue related to hardened grease.

A loose post (end not a loose guide) is something else where the post itself is no longer "crimped" in its socket. If you try to rotate the head of the post, the whole post will rotate (including the locking nut at its base).
 
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