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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 15th Jun 2021, 7:29 pm   #1
DMcMahon
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Default Uher CR 210 Cassette Recorder Check Out

Just quickly looking at this CR 210 which is a smaller and simpler sibling to my CR 240.

Sold as not working, with status that powers up but no drive and on/off push button stuck in/down. No AC/DC adapter/charger but did come with a Uher Z 215 NiCad rechargeable battery (fully flat). Came with a somewhat tatty leather case and a bunch of cables plus useful User manual and the very useful large service/schematic sheet.

Found that the stuck down push button is the on/off switch for the internal loudspeaker, have managed to get this moving a little.

Using my Z 131 power adapter from my CR 240 (the 210 uses the same adapter) got it to power up, although somewhat intermittently. Like the CR 240 the cassette tape has to be fitted and lowered down for the unit to power up.

The motor tries to rotate and the main drive belt does move but no sign of the cassette tape moving. Motor speed/direction does not change with FFD, RWD, FWD or Reverse selected. Very difficult to tell properly without a strip down but the 4 belts look intact.

Presently charging the Z 215 battery to see if it will take and hold a good charge.

Will need to do a strip down to check out the belts properly which I am not looking forward to, everything is crammed in so tightly and very delicate.
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Last edited by DMcMahon; 15th Jun 2021 at 7:33 pm. Reason: Typo correction
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Old 15th Jun 2021, 11:14 pm   #2
Uncle Bulgaria
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Default Re: Uher CR 210 Cassette Recorder Check Out

I've got a CR 210 in bits here so can provide cross-checking on the internals if necessary. The battery's intriguing - I've never seen one and have wondered if one could be re-engineered or re-stuffed with new cells. It would be a little more convenient than a load of C cells, as mine has when it's on walkabout..
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Old 16th Jun 2021, 7:31 am   #3
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Default Re: Uher CR 210 Cassette Recorder Check Out

The Z 215 battery appears to have charged OK. Off load it currently measures 8.3V, in the machine the VU/battery strength meter indicates half way (7V), with only the Z 131 (24V) adapter plugged in the meter indicates full scale (> 8V).

Will see how the battery lasts out.

David
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Old 18th Jun 2021, 9:21 am   #4
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Default Re: Uher CR 210 Cassette Recorder Check Out

Removed the cassette carriage assembly. Now can see that the belts from the 2 flywheels to the 2 spool clutches are quite slack, also the main drive belt from motor pulley to the flywheels, so will get a set of new belts.

With main belt slipped off the motor pulley can see that motor pulley basically just oscillates (sometimes is just stationary) when unit is powered up and by touching the motor drive board can sometimes get the motor to spin at high speed. Looks like some sort of bad connection on the board maybe.

Cannot remember from my previous CR 240 work if the motor normally rotates/spins when unit is powered up (with no tape transport demand), if I could only find my 240 then I could check it out.

Since removing the cassette carriage, now have some control of the play and reverse pinch roller arms moving to the respective capstan shafts when Play or Reverse is selected. This control is intermittent and once again looks like bad connection/contact somewhere.

David
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Old 18th Jun 2021, 9:38 am   #5
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Default Re: Uher CR 210 Cassette Recorder Check Out

The charged Z 215 Ni-Cd battery did not last long, now fairly flat after very minimal usage, will try charging again.

David
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Old 18th Jun 2021, 4:23 pm   #6
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Default Re: Uher CR 210 Cassette Recorder Check Out

The motor and tape mechanism is basically the same as the CR 240, if not exactly the same. The motor won't start until a tape is inserted, and with the mechanism out you can deceive it by pressing switch K3. Here're the relevant bits from the CR 210 manual. I have the originals, so if you're bereft I could try to scan them.
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Old 18th Jun 2021, 4:39 pm   #7
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Default Re: Uher CR 210 Cassette Recorder Check Out

I have the original large schematic thankyou Uncle Bulgaria.

Yes with cassette carriage out I am deceiving it by pressing K3, K3 has to be actuated to get power on. What I was not so sure about is should the motor start as soon as K3 is pressed or only when Play/Reverse/FFD/RWD is selected after pressing K3.

David
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Old 18th Jun 2021, 4:49 pm   #8
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Default Re: Uher CR 210 Cassette Recorder Check Out

I should have said that the large schematic has similar servicing info as per your Service manual sheets but not as detailed.

Did you get the manual from SDS or found it online ?

David
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Old 18th Jun 2021, 4:50 pm   #9
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Default Re: Uher CR 210 Cassette Recorder Check Out

Marvellous! These Uher drawings are brilliant. Mine came with a 16 page booklet and two large fold-out sheets for the PCBs. If you're missing anything I'm sure I'll be able to send over the relevant information.

The motor will only start when the machine's on, and a cassette has been inserted and lowered such that K3 is actuated. The motor will start as soon as K3 is closed, and will continue to run as long as the cassette is loaded, presumably so it's ready as soon as any of the controls are operated.

Edit: I think they're from SDS when I got the belts. I put the belt sizes in that other recent thread about a CR 240 as they're shared with the 210. The booklet's entitled "Uher Service CR 210 Stereo" and the two sheets are "AF- and Power Supply Circuit Diagrams" and "Drive assembly control electronic and Motor electronic".
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Old 18th Jun 2021, 4:54 pm   #10
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Default Re: Uher CR 210 Cassette Recorder Check Out

Many thanks Uncle Bulgaria for the confirmation, that is what I thought and what I think I remembered from the 240 work but because the motor often will not work, sometimes just slowly oscillating and sometimes can be induced to spin by touching the motor drive board I did wonder if my 240 memories were correct.

David
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Old 18th Jun 2021, 5:02 pm   #11
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Default Re: Uher CR 210 Cassette Recorder Check Out

It's probably one of those tiny solid wires they like to use, which fracture and cause intermittent contacts. If the motor's the same as the CR 240, it is possible to take it apart and clean it up. It's a faff though so I wouldn't recommend it unless you've ruled out any intermittent connections on the boards. Maybe it just needs a few runs to polish off any corrosion on the contacts. I did replace the isolation foam on the motor casing on my CR 240 as it was crumbling to dust that was likely to cover the tape mechanism...
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Old 18th Jun 2021, 8:39 pm   #12
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Default Re: Uher CR 210 Cassette Recorder Check Out

Thank you for the motor information, I hope I don't have to take it apart although it would be interesting to see inside it

I think the motor foam looks OK.

David
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Old 20th Jun 2021, 9:51 pm   #13
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Default Re: Uher CR 210 Cassette Recorder Check Out

Removed the Flywheels assembly for drive belt replacement, all 4 belts are stretched and will require replacement. They are square section so probably are the original belts, have ordered a set of round belts.

No progress yet on the motor drive issue, seems to have got worse, before could sometimes get it spinning by touching the Motor Drive board, now much more difficult to get it to spin, mainly just slowly oscillates sometimes.

Need to try and monitor the motor signals to see what is happening. Even though I have the large Schematic/Service Sheet, I find it difficult to read/follow the connections, will scan the relevant sections and print out A3 size.

David
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Old 20th Jun 2021, 11:45 pm   #14
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Default Re: Uher CR 210 Cassette Recorder Check Out

There is a small wired lamp (grain of wheat type) on the Automatic reverse impulse transmitter board, struggling to see this lamp on the schematic. The lamp is not lit.

David
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Old 21st Jun 2021, 8:20 am   #15
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Default Re: Uher CR 210 Cassette Recorder Check Out

Have now worked out what the lamp is.

On the schematic there is an 8V 40mA lamp shown within a green sectioned area, there are also in/out connections to this green area from K3, K4 and another contact. The green areas are normally PCBs/section of PCBs but this particular section is not identified.

One side of the lamp connects to ground and the other side connects out to contact K2. With contact K2 made/closed the +9.7V supply will be switched through to the lamp.

The giveaway clue to the identified sectioned PCB is that its external connections are numbered in the 900's and the external connections shown on the Automatic reverse impulse transmitter PCB are also numbered in the 900's, so the unidentified green section is part of that PCB.

The schematic lists K2 location as "at the volume control" and User manual says that when the Volume control is pressed in, it will illuminate the cassette inspection window (the PCB is situated below this), now of course remember this lamp from the CR 240.

Pressing the volume control does illuminate the lamp.

David
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Old 21st Jun 2021, 3:03 pm   #16
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Default Re: Uher CR 210 Cassette Recorder Check Out

Quote:
Originally Posted by DMcMahon View Post

The giveaway clue to the identified sectioned PCB is that its external connections are numbered in the 900's and the external connections shown on the Automatic reverse impulse transmitter PCB are also numbered in the 900's, so the unidentified green section is part of that PCB.

David
The giveaway clue to the un-identified sectioned PCB is that its external connections are numbered in the 900's and the external connections shown on the Automatic reverse impulse transmitter PCB are also numbered in the 900's, so the unidentified green section is part of that PCB.
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Old 21st Jun 2021, 9:07 pm   #17
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Default Re: Uher CR 210 Cassette Recorder Check Out

Been checking out the motor connections, all 3 motor windings measure around 13 Ohms measured at the Motor Drive board via the commoned end of the motor windings that connect to the +9.7V supply, so look good.

Not able to get good readings across the 3 motor distributer contacts, on the schematic and in description 2 of the contacts should be grounded and as the motor rotates the grounded pair should cycle around the 3 contacts. Not able to measure any of the contacts being properly grounded, mainly hundreds of Ohms but nothing consistent at all. Measured the ground connection is getting to the motor at terminal 4. So looks like there may be a problem with these contacts but somewhat loath to go inside the motor to check as looks so difficult but may have no option.

Struggling at the moment to measure the +9.7V supply at the Motor Drive board, there must be voltage there because the motor does rotate sometimes, think just bad meter connections, everything is so awkward to get onto, made more difficult by having to press down K3 to get power on.

Uncle Bulgaria - How does the motor drive pulley come off the motor shaft ? and how do the black end caps come off the motor. From your motor photos I assume the 3 contacts are the sprung loaded pins that make contact with the 3 copper segments in the end cap. I think I am going to have to bite the bullet and remove the motor for disassembly to inspect the contacts but first will check the motor drive signals and contacts voltage wise when the motor runs

David
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Old 22nd Jun 2021, 10:10 pm   #18
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Default Re: Uher CR 210 Cassette Recorder Check Out

Measured the +9.7V supply at the Motor Drive board as around 8.1V, so somewhat low but do not think this has any connection to the motor control problem but will have to check it out later.

Scoped the 3 motor drive signals, all 3 very similar a square pulsed (10mS) with repetition rate of around 40mS so around 25Hz, between 0V and +8V, even though not pretty, as all 3 are doing basically the same I think the main drive electronics is probably OK.

Scoped the 3 motor distributer switch lines, all very similar, a rough waveform with squarish +ve peak and spikey/sawtooth -ve peak (with noise spikes at times), switching between around +2V and -2V. Continuity/resistance checks of these 3 connections to ground as before gives very inconsistent highish resistance connections to ground.

In early stage of removing the motor which as expected is very difficult, hopefully I can get inside the motor and checkout the 3 switched contacts.

Update - forgot to say that becoming increasing difficult to get the motor to spin/rotate, sometimes by manually spinning the motor pulley gets it going for a while. The waveform info above is when the motor is spinning.

David
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Old 22nd Jun 2021, 10:21 pm   #19
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Default Re: Uher CR 210 Cassette Recorder Check Out

The motor pulley pulls off the shaft. I don't remember it being too difficult. Have you tried leaving it running in case that cleans off the internal contacts? Perhaps the 'Uher rattle' as it gets up to speed will help as well.

Have you traced the ground connections?

I remember the CR 240 boards having some easier positions to access the contacts - instead of the tiny pins on the connecting plugs, for example, some go to more widely-spaced plated holes on the board that take a probe better.

If you're set on disassembling the motor, it looks just like the CR 240. There will likely be some tabs on the silver casing to lever out of the way, allowing the end caps to slide out. You can see these in my photos above.
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Old 22nd Jun 2021, 10:28 pm   #20
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Default Re: Uher CR 210 Cassette Recorder Check Out

Thank you Uncle Bulgaria.

Yes have checked the ground connections as far as I can to the Motor Drive board, on the Motor Drive board and out to the motor, all check out OK.

I tried pulling the pulley off with the motor in position but no joy, hopefully when the motor is out can get a better grip of it and it will come off.

David

Update - Yes have left it running for quite a while, often requiring manual help to restart it when it stops spinning

Last edited by DMcMahon; 22nd Jun 2021 at 10:31 pm. Reason: Update
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