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  #1  
Old 10-05-2016, 04:25 AM
colectorad colectorad is offline
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1982 jvc hr-7300u









There are five belts in this unit:



The square take up belt that runs from the top of the capstan to a white pulley was about 48 mm in diameter. When I replaced it with a new one of the same size, it didn't work. So, I tried smaller sizes until the take up reel turned reliably. ~40 mm did the trick.

The flat capstan belt was completely melted. It appears to have been about 101 mm in diameter. I didn't have a replacement, so I made one out of vinyl electrical tape. After six hours of testing, it still works consistently.

The loading motor belt was fine and hasn't been measured.



The counter mech uses two belts. The first is ~63 mm in diameter and goes from the take up reel to a double pulley.



The second belt goes from the double pulley to the counter mech. It's about 32 mm in diameter.



There are several date code locations including: the inside of the front panel, the forward/reverse motor, and the top of the loading mech (month & day). As you can see, this unit was manufactured in December of 1982.
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I'm in need of service manuals for the following:

Magnavox 19C315-CC, Emerson ECT-1300A (TM0110E), Sears 401.50300900

Last edited by colectorad; 10-07-2016 at 02:49 AM.
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Old 10-05-2016, 07:02 AM
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Unless that flat belt was wider than 1/4" I'd have made it out of rubber bands...if the band is too long or short splice it with another band and super glue.
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Old 10-05-2016, 03:48 PM
centralradio centralradio is offline
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I tried the rubber band fix which is ok and not on the capstan drive unless you want quivering sound and a shaky picture.LOL....................
One of my main apps for the rubber band trick is the capstan belt of a Toshiba beta HiFi (the original is almost exactly rubber band size) it's always ran smooth as silk with a rubber band there..... I've never known where or how to order belts so most of my mechanical equipment that did not have good belts or use ones from gear I've scrapped are 'living on office supplies' so to speak.

Last edited by Electronic M; 10-05-2016 at 04:01 PM.
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Old 10-05-2016, 07:20 PM
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Looks like you can still get a belt kit from http://studiosoundelectronics.com/mbk-06.htm to restore it properly.

3 kits: Belts only, with rubber tires, and with pinch roller.
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  #5  
Old 10-07-2016, 10:52 AM
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What a cool project! I've only seen one of those models back in 1999 when I put new belts on it. Hope you get it working again!
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Old 10-08-2016, 06:43 PM
colectorad colectorad is offline
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Quote:
Originally Posted by Electronic M View Post
Unless that flat belt was wider than 1/4" I'd have made it out of rubber bands...if the band is too long or short splice it with another band and super glue.
This machine isn't mine and it's mostly in storage. I don't want a rubber band dry rotting in it. Folded vinyl electrical tape wont leave a mess when the time comes.

Quote:
Originally Posted by Blast View Post
What a cool project! I've only seen one of those models back in 1999 when I put new belts on it. Hope you get it working again!
Let me clarify:

This unit 'works' as it is. All it could use outside of a proper capstan belt is a sealed relay. The 'Omron 62V-2' relay that it uses appears to have never been reliable by design. SP playback & reverse search suffer from it. I've seen mid-'80s recordings made by this machine with interference from the relay not switching the heads over all the way.
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I'm in need of service manuals for the following:

Magnavox 19C315-CC, Emerson ECT-1300A (TM0110E), Sears 401.50300900
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  #7  
Old 10-09-2016, 08:28 AM
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Quote:
Originally Posted by colectorad View Post
All it could use outside of a proper capstan belt is a sealed relay. The 'Omron 62V-2' relay that it uses appears to have never been reliable by design. SP playback & reverse search suffer from it. I've seen mid-'80s recordings made by this machine with interference from the relay not switching the heads over all the way.
Yes, I remember when head switching relays were a problem in earlier RCA/Hitachi models, as well. Back in the 90's I knew the part number for the relay by memory.
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Old 10-09-2016, 09:20 AM
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JVC started supplying hermetically sealed relays to replace those that failed. Never saw one of the sealed ones fail. Recognizable because they are solid black, not the clear cover like the originals. I remember at one point JVC started putting glue around the clear cover to try and keep the contacts from getting oxidized.
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  #9  
Old 10-26-2016, 03:34 AM
colectorad colectorad is offline
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Quote:
Originally Posted by Ed in Tx View Post
I remember at one point JVC started putting glue around the clear cover to try and keep the contacts from getting oxidized.
That's exactly what they did here (too bad it didn't work):



There are quite a few compatible replacements for it. I can't find any that match the dimensions (~20.5 X 11 X 12mm), though.
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I'm in need of service manuals for the following:

Magnavox 19C315-CC, Emerson ECT-1300A (TM0110E), Sears 401.50300900
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  #10  
Old 11-01-2016, 06:51 PM
djfivos djfivos is offline
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See this video:

https://www.youtube.com/watch?v=eYYAg965Zqk
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  #11  
Old 11-01-2016, 06:59 PM
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Quote:
Originally Posted by colectorad View Post
That's exactly what they did here (too bad it didn't work):



There are quite a few compatible replacements for it. I can't find any that match the dimensions (~20.5 X 11 X 12mm), though.
I might have one. If I do I will send it to you. What does it say on the clear top of the relay Voltage & Ohms?
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  #12  
Old 11-03-2016, 04:27 AM
colectorad colectorad is offline
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Quote:
Originally Posted by Ed in Tx View Post
What does it say on the clear top of the relay Voltage & Ohms?
12 volts and what looks to be 310 ohms.
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I'm in need of service manuals for the following:

Magnavox 19C315-CC, Emerson ECT-1300A (TM0110E), Sears 401.50300900
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  #13  
Old 11-03-2016, 07:12 AM
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The one I have is a 9V version, the one they used in the JVC portable HR-2650. I suppose you could add a resistor in series with the coil and use it.

However I found some on ebay, used, but 3 mo warranty.

No affiliation btw...

http://www.ebay.com/itm/160891770319...&sojTags=bu=bu
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  #14  
Old 11-06-2016, 03:32 AM
colectorad colectorad is offline
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What about this?
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I'm in need of service manuals for the following:

Magnavox 19C315-CC, Emerson ECT-1300A (TM0110E), Sears 401.50300900
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  #15  
Old 11-06-2016, 09:17 AM
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Looks like it should work. Not sure what the variations of the part number mean, no specs available I could find.
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