razpones
Member
Hello everyone, I write today because what I thought would be an uncomplicated repair, became a nightmare.
It all started with a working deck, the problems were, the tray was not opening consistently and the motor would start operation as normal but after a few minutes would slow down to a crawl and make a screeching noise.
So I thought I would try and lubricate the motor, it is the main motor.
I could never find the service manual so i downloaded a manual for a similar deck (tho a much more fancier and expensive one), the DRS-640, also a horizontal loading tape deck. https://www.hifiengine.com/manual_library/denon/drs-640.shtml
I went thru the disassembly and it all seemed fine. Got to the motor and opened it, clean and lubed it, and put it back together.
I then proceeded to marry the tray and the mechanism together. Seemed to come together well, put it back in the case, connected all wires and gave it a try. The tray would not open, and when i opened it by moving the gears by hand it would get stuck at the part where the arm that pushes the tape down, got down to push.
I thought it might be a weak belt so i started to try different belts but none would work. It had no problem closing the tray, but it would not open. I disconnected all wires and started to look at the mechanism for clues.
After checking out some photos i took while i was disassembling the unit, I noticed a white lever of sorts that seemed to sort of engage and disengage the arm from being in tension. So i put it where the picture was showing and sure enough the tray started to work right when i did it by hand, but it wouldn't do it electrically.
At this point, I forgot the tray for a bit and decided to try to see if would play a tape, loaded one and push play. Weirdly it FF and RW, but when i tried play it played at double speed and no sound, i think the head did not lift. So took it off the case and disconnected all wires, thinking maybe i didn't connect the computer flat wire correctly, checked the transport for something wrong, but couldn't find anything, So again I connected it back into the board this time making sure all wires were sitting right. The tape played at normal speed but only one way and no sound, the other way would not play and the screen said end of tape, so something wasn't right again. disconnected all again and reconnected. Not finding anything obviously wrong with the mechanism.
At this point i was trying to load the tape back and pushed the little switch that sits next to the tray, a pair of plates that come together when the tray is next to them and open when the tray is open and out of the way. I thought that might be the issue with the tray not opening so i pushed it against the tray closing it tighter and pushed the button to open, and yes, it opened, so i cleaned the contacts with a very light sand paper (but i forgot to turn off the deck, which might be the thing that made the next thing happen).
After the contact were clean, the tray opened and closed no problem, nothing seemed untoward, nothing seemed wrong at this moment. So cassette in tray, tray working, I went ahead and pushed play. Headphones on, a buzz came on as soon as play was pushed (speed was correct though), I thought, this is bad. And sure enough, one of the little transistors in the area where all motors and tray switch connect started to smoke!!!!
So now am totally lost as to why this happened. I don't know if by cleaning the switch while it was on was the problem, but nothing happened at that time. Help! I really like this deck it is unusual and when it played, it sounded quite good. I am posting photos of the connectors close to the transistor, and the switch i mentioned and also the transistor.
The transistor is labeled D1111 1H on it's face, it is TR513 on the board, and not sure if this might or not be the same, but on the manual for the other deck DRS-640 it is called DTC143ES(4.7K-4.7K) T built in resistor.
I went looking for it, but all i found was a surface mount version of it. I'm planning on calling Mouser on Monday to inquire about it.
Any help is welcomed, am totally lost on why this happened, as i never touched the main logic board other than to push the connectors of the wires in. The last time I connected all wires i made sure to double check they were sitting right and no wires were crossed or touching or going into the wrong hole (for the one computer type flat cable).
Thanks for any help!
It all started with a working deck, the problems were, the tray was not opening consistently and the motor would start operation as normal but after a few minutes would slow down to a crawl and make a screeching noise.
So I thought I would try and lubricate the motor, it is the main motor.
I could never find the service manual so i downloaded a manual for a similar deck (tho a much more fancier and expensive one), the DRS-640, also a horizontal loading tape deck. https://www.hifiengine.com/manual_library/denon/drs-640.shtml
I went thru the disassembly and it all seemed fine. Got to the motor and opened it, clean and lubed it, and put it back together.
I then proceeded to marry the tray and the mechanism together. Seemed to come together well, put it back in the case, connected all wires and gave it a try. The tray would not open, and when i opened it by moving the gears by hand it would get stuck at the part where the arm that pushes the tape down, got down to push.
I thought it might be a weak belt so i started to try different belts but none would work. It had no problem closing the tray, but it would not open. I disconnected all wires and started to look at the mechanism for clues.
After checking out some photos i took while i was disassembling the unit, I noticed a white lever of sorts that seemed to sort of engage and disengage the arm from being in tension. So i put it where the picture was showing and sure enough the tray started to work right when i did it by hand, but it wouldn't do it electrically.
At this point, I forgot the tray for a bit and decided to try to see if would play a tape, loaded one and push play. Weirdly it FF and RW, but when i tried play it played at double speed and no sound, i think the head did not lift. So took it off the case and disconnected all wires, thinking maybe i didn't connect the computer flat wire correctly, checked the transport for something wrong, but couldn't find anything, So again I connected it back into the board this time making sure all wires were sitting right. The tape played at normal speed but only one way and no sound, the other way would not play and the screen said end of tape, so something wasn't right again. disconnected all again and reconnected. Not finding anything obviously wrong with the mechanism.
At this point i was trying to load the tape back and pushed the little switch that sits next to the tray, a pair of plates that come together when the tray is next to them and open when the tray is open and out of the way. I thought that might be the issue with the tray not opening so i pushed it against the tray closing it tighter and pushed the button to open, and yes, it opened, so i cleaned the contacts with a very light sand paper (but i forgot to turn off the deck, which might be the thing that made the next thing happen).
After the contact were clean, the tray opened and closed no problem, nothing seemed untoward, nothing seemed wrong at this moment. So cassette in tray, tray working, I went ahead and pushed play. Headphones on, a buzz came on as soon as play was pushed (speed was correct though), I thought, this is bad. And sure enough, one of the little transistors in the area where all motors and tray switch connect started to smoke!!!!
So now am totally lost as to why this happened. I don't know if by cleaning the switch while it was on was the problem, but nothing happened at that time. Help! I really like this deck it is unusual and when it played, it sounded quite good. I am posting photos of the connectors close to the transistor, and the switch i mentioned and also the transistor.
The transistor is labeled D1111 1H on it's face, it is TR513 on the board, and not sure if this might or not be the same, but on the manual for the other deck DRS-640 it is called DTC143ES(4.7K-4.7K) T built in resistor.
I went looking for it, but all i found was a surface mount version of it. I'm planning on calling Mouser on Monday to inquire about it.
Any help is welcomed, am totally lost on why this happened, as i never touched the main logic board other than to push the connectors of the wires in. The last time I connected all wires i made sure to double check they were sitting right and no wires were crossed or touching or going into the wrong hole (for the one computer type flat cable).
Thanks for any help!
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