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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 12th Sep 2020, 5:04 pm   #21
Uncle Bulgaria
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Default Re: Uher CR 240 AV Cassette Recorder

I'd start a new thread with your specific problems for your unit, as this thread is for DMcMahon's issues so replies can get very confusing. I'm sure the Mods can move these replies to a new thread for you. [Mod edit: Now done]

In answer to your question, the yellow 'on' is on when the volume knob has turned the unit, er, on. When you engage 'play', this goes out and the green light comes on, returning to yellow when the tape stops.
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Old 13th Sep 2020, 1:23 am   #22
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Default Re: Uher CR 240 AV

I have a constant yellow and green light once the machine is powered up, regardless of tape transport driving. All three light up on record. Still, its not a problem re. sound quality , which is remarkable, to my mind, for cassette. True I've never dabbled with a high end cassette machine before, still, well impressedwith the little Uher.
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Old 13th Sep 2020, 1:37 am   #23
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Default Re: Uher CR 240 AV

Hmm. Not all is well with the transport section then. Attached is the relevant part of the output. As you can see, the lights are all wound up with the parts marked 500 and 15, which are the coils for the solenoid that engages the heads. It strikes me that you might want to check through some of the continuity of the switches.

What should happen is:

Turn on - yellow light turns on. Move joystick to 'stop', press 'record', red light comes on, move joystick to 'pause', record switch stays locked in with yellow and red lights on. Move joystick to 'play', red and green lights are on, yellow goes off. In playback, only the green is on.

Mine does sound unexpectedly good, too! When lockdown commenced, I recorded the Queen from the TV with Dolby, after sorting out noise on that circuit, and even through the built-in speaker the quality is really something. I bring her out at unexpected moments when I feel the situation needs a bit more gravitas.

Addendum: I have a CR240 not an AV. There may be differences, but it seems unlikely that Uher would have changed the behaviour of the lights. Just check the AV circuit diagram in case, and compare it to the one I attached, which is valid from serial number 162 407 000.
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Old 13th Sep 2020, 10:38 am   #24
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Default Re: Uher CR 240 AV

Make sure the connection between point 107 on the 100 board and point 718 on the 700 board and the through connections to the junction of the LED's D101 & D102 and the junction of T701 & T702 is ok, that's the common switching feed that shuts off the On and Play LED's.

Lawrence.
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Old 13th Sep 2020, 3:29 pm   #25
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Default Re: Uher CR 240 AV

Thanks for the info Lawrence.
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Old 14th Sep 2020, 11:26 pm   #26
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Default Re: Uher CR 240 AV

Checked out the 700 board and seems to be ok. Will need to do the less easy to get at 100 board another time. Also the 1000 board as I'm not getting any volts at the meter bulbs either. Apart from the wayward transport leds and meter/tape compartment lighting, everything else seems ok. 12v psu turned up today, 8pin DIN plug still to come, so this might help with the bulb issue as it bypasses the timer circuit when on cells only, I believe.
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Old 15th Sep 2020, 2:36 am   #27
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Default Re: Uher CR 240 AV

Yes, with a Z131 or 12V in at the AutoRadio then the bulbs light all the time. The bulbs are in series, so you can't check them individually. Make sure you're checking operation at the transistor T10.
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Old 15th Sep 2020, 1:30 pm   #28
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Default Re: Uher CR 240 AV

Ok bulbs in series makes sense, 3x 3volt bulbs =9V. I wonder if you know which point on board 1000 is the 9 or 0 volt point?
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Old 15th Sep 2020, 2:30 pm   #29
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Default Re: Uher CR 240 AV

So far as I can make out from the 1000 board layout, 1014 is the 9 volts connection and 1012 is the ground connection.

Lawrence.
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Old 15th Sep 2020, 2:38 pm   #30
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Default Re: Uher CR 240 AV

Totally agree with Lawrence. On the 1000 board component layout drawing, it shows a 5 way ribbon cable connected near top right hand corner with top connection being 1010 and bottom connection being 1014, so 1012 should be the 3rd ribbon cable connection down on that layout.

David
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Old 15th Sep 2020, 3:06 pm   #31
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Thanks very much guys.
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Old 15th Sep 2020, 3:17 pm   #32
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Default Re: Uher CR 240 AV

Quote:
Originally Posted by Uncle Bulgaria View Post
The bulbs are in series, so you can't check them individually.
This has got me wondering why my VU meter lamps light but not my counter/cassette lamp, maybe the cassette lamp has failed short circuit ?
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Old 15th Sep 2020, 3:30 pm   #33
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Default Re: Uher CR 240 AV

You'll notice D1002, the green LED on board 1000 is connected to ground in the centre between the two meters, which I found handy for voltage readings. I had to repair some of the track on mine and changed to LEDs at the same time.

Yes David, the counter lamp on board 100 is in series with the cassette lamp on board 800, so I had one that was still working but the other having failed meant neither lit. I ended up doing the LED replacement with both.
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Old 16th Sep 2020, 11:28 pm   #34
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So it looks like ther are 4 3v bulbs! The two for the vu lamps in series and the two for counter and tape compartment in series, if I'm reading the diagrams correctly. It looks like the ones on the meters should unclip and be easy to swap for leds, with plenty of room for a dropper resistor too. Leds, Din plugs etc all here now so another go at the weekend! My meter board is a green one!

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Old 17th Sep 2020, 1:05 am   #35
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Default Re: Uher CR 240 AV

Quote:
Originally Posted by DMcMahon View Post
Quote:
Originally Posted by Uncle Bulgaria View Post
The bulbs are in series, so you can't check them individually.
This has got me wondering why my VU meter lamps light but not my counter/cassette lamp, maybe the cassette lamp has failed short circuit ?
I misunderstood the "bulbs are in series" comment to mean that all 4 are in series together, which I can see now is not the case.
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Old Yesterday, 12:55 am   #36
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Default Re: Uher CR 240 AV

The supply to the bulbs on the meter board measures 5.7V to ground, with batteries as power source. I've replaced both bulbs with white LEDs, though only one had failed. They are a little less bright than I would like however. Perhaps there is a resistor downstream that might be possible to swap out?
Today has been one of trying to get a reliable feed using the 12v Auto socket and 12v psu. To cut a long story short, all the connections and tracks on the board are ok, but the supply is intermittent and seems to be a problem with the safety cutout on the din socket itself, which cuts off the C cells. As I've no intention to use C cells or a battery pack, is there a way to bypass this feature to make a permanent contact for the 12v supply whilst still using the 8pin din plug, which is a Deltron quality item btw.
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Old Yesterday, 10:56 pm   #37
Pine Marten
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Default Re: Uher CR 240 AV

Leaving the 8pin din socket to soak overnight with servisol has now ruled this out. With the psu connected and board loose there is power. Wiggling the plug or slightly bending the board to and fro or moving the ribbon cables does not provoke an intermittent. However once fixed back in the machine, nothing doing. I assume the small bit of thin plastic with the hole in, the size of the power transistor, goes between that and the case. Likewise the two standoffs for the board, plastic one at bottom, metal one at top for the screws going into the socket housing?
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Old Yesterday, 11:18 pm   #38
Uncle Bulgaria
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Default Re: Uher CR 240 AV

Yes. There's a pretty good search function at the top of the page. See one of my (many!) CR240 threads on this for my struggles with the BD241. Mine came without the mica insulator, so whenever I had the PSU board in the case nothing ran, but did as soon as I had the board out. I now know because the transistor was isolated from the chassis, whereas connected without the mica washer it was grounded and shorting out.

The metal standoff goes to the copper ring on the upper of the two screw holes. The nylon is the lower. The BD241 has a mica insulating TO220 washer between it and the case, and an insulating standoff between the heatsink and the board so the screw doesn't touch the transistor's heatsink.

I don't know about your LED problems. Mine were far too bright, so I had to keep increasing the current limiting resistors above what I'd calculated.
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Old Today, 11:24 am   #39
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Default Re: Uher CR 240 AV

If the BD241 isolation is not the issue then I would have another close visual look at the 2 ribbon cables soldered connections at both ends going from the power supply board to the main board. I had a bunch of bad dry joints on the 6 way ribbon cable from the power supply board to the battery/power adaptor connector block.
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Old Today, 1:23 pm   #40
Pine Marten
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Default Re: Uher CR 240 AV

I suspect something is losing contact once everything is squashed into place in the case. The ribbon cables are not particularly flexible so I will start with these. I'm pretty sure its not a component failure its got to be a poor solder joint or track issue.
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