SONY 8mm VCR Playback and Unload/Eject Problems EV C3

Hi David,

It's not as if this machine is very valuable (although it was originally about $800, not a $50 VHS), but like you, I'd prefer to have it working instead of laying in a landfill.

I received this response from David F regarding the VCR problems:

Hi WB,

For some reason, my news server didn't post my response to your question. Basically, replacing the caps in the head amp will fix all the picture, tracking, speed problems.

As far as the loading mechanism goes, remove a wire from the loading motor and power it with a small amount of voltage from your power supply. When you notice it doing something out of the ordinary, immediately remove the power and investigate what might be causing it to jam. Perhaps a worn tooth on a gear?

Good luck.

-- David Farber David Farber's Service Center L.A., CA

I don't want to be unduly pessimistic, but Sony's 8mm transports are, to put it kindly, delicate. I had the transport in a HandyCam and home VCR fail for no obvious reason, with parts bending or breaking. The VCR is currently non-functional, with erratic loading.

Narrow tape formats require small transport components, which are difficult to make "robust".

I know what you mean.. I have a SONY 8mm camcorder with a short round section of pin (approx 1/8" long) that separated from something in the tape transport (which may be the only thing wrong with it), but I'm lacking the enthusiasm to start disassembling the mechanism to see if it's original location can be found.

The tape transport in the EV C3 VCR is described as being the same one used in commercial 8mm decks, so it's not quite as flimsy as the consumer version seen in camcorders, just not a lot better in design, though.

-- Cheers, WB .............

Its too bad that there wasn't cross-licensing with Exabyte; the EXB8900 transport is the model of robustness and elegance with few moving parts beyond motors. It could have been the basis for 8mm video products as well. I recommend reading the patent literature online for detailed descriptions of the Mammoth transport.

Michael

I just sold a Sony Digital 8 camera I bought in 2000 that was well used but perfect in function. If the mech is treated with respect and warnings followed there isn't any reason it should unduly fail under normal use for many years. I would say this is the case in the majority the minority being misuse and manufacturing QC.

I wish that were so, but I've had two analog units fail -- and I'm not aware of having abused them. In both cases, the failures were abrupt, and not preceded by any action that might have caused them (that I'm aware of).

For what it's worth... I rarely have problems with any of my electronics or photographic equipment.

Me either. Maybe the digital mech is more robust? I do have a Sony Mini DV that I really like but the CCD failed after only 5 years. The touch screen lost its backlight after 3 yrs from a loose connection that I did repair. I replaced it with a Panasonic GS320. The 3 CCD pickup and the OIS are a dramatic improvement over the Sony but I do miss the night vision. Maybe one day I'll come across a Sony mini that needs a mech. I have one in the scrap bin :L)

If anyone has a SONY service manual for the EV C3 model and the U mechanism, and/or the tiny belts and pinch roller, that they would like to sell, please let me know. wb(underscore)wildbill at yahoodotcom

I tried using a small 2-AA battery holder with plain leads to check the tape loading motor operation of running the guide bloks forward and back several times, and noticed no resistance to movement or jamming.

Then I made a 3-AA tester "motor exerciser box" using a battery box and a DPDT and a momentry switch, with clip leads, for easier/more reliable reversing of the motor, and ran it thru many more cycles with the same results. There is no tape in place for these tests, since I would need to have control of more functions of the Syscon board, such as the reel spindles and possibly brakes. I did try putting a rubber band on the guide posts (individually) to add a little load, but the guide post blocks still operated as they should.

As mentioned earlier, the weird operation is the tape guide blocks running back 'n forth while trying to unload the tape (before Syscon even activates Cassette Eject).

It looks as if Syscon can't make up it's mind which way to move the tape guide blocks to unload the tape.

Unload tape, Start Starting, OK Wait a sec, other way Other way, OK Uh-oh, wrong way Huh? Go back Going back, OK No wait, reverse Reversing, OK Nevermind, taking too long Nevermind, OK Quit now Quit, OK Breaktime! Naptime, OK

As anyone knows that's ever serviced these small machines or camcorders, it's difficult to run the mechanisms thru the various functions to see what's happening, if one doesn't have all the various extension cables to enable the mechanism to run outside of the main unit chassis.

Reel sensors were cleaned? with gas duster, although the interior of this machine was extremely clean. Mode switch had a couple of drops of DeoxIT applied, not removed for examination, although it's probably the next best place to look for trouble.. damage/wear, dirt or oxidation. Mechanical load parts have had a minute amout of grease added after cleaning off excess. The underside of the mechanism appears to be undamaged. The reel spindles turn freely with the machine off and unloaded.

It looks a little odd, that if I stop one guide post block (with tension on the rubber band), the guide post block on the other side continues to travel.. I dunno if that's normal or not.

-- Cheers, WB .............

As this project continues (drags on).. I disovered that the bottom large board swings out, so there is fairly good visual access to the bottom of the transport mechanism, after the Servo/Syscon board is also swung out of the way.

With the top and bottom covers off, and the unit standing up on it's right side (facing the front), the bottom board is attached to hinged signal connectors, so it can swing down to the benchtop after 2 screws are removed. Then the Servo/Syscon board directly under the mechanism can be unlatched and swung down after removing 1 screw, and releasing the capstan motor harness from the plastic anchor.

It may be necessary to connect some temporary jumpers from the pads where the removed screws would ground the boards, to the chassis, in order for the board grounds to be maintained. I thought I had them both grounded properly, but the key funtions (FF, Rew etc) didn't work while I had the boards dropped down. However, Eject did work smoothly a few times, without floundering.

After this initial test, I put the boards back in place with the screws, and tested cassette loading and numerous Eject cycles without any problems.

With a little more manipulation, the ribbon cable in the corner of the Servo/Syscon board can be coaxed to come out of the corner where it's folded over, so some more range of movement is possible to get the board down and away from the transport mechanism. The Mode Switch still isn't visible, as it's view is blocked by the small board at the front, but the majority of the mechanism is visible.

While examining the bottom large board (Video, Video I/O, RF Block, Jog), I noticed that C219 470uF 10V (Red case, Long Life brand) was wet around the seal. This cap is a radial lead type, but the leads are bent 90 degrees, so it will lay on it's side on the board. After replacing C219, I put a little DeoxIT on the hinged connectors along the edge of the board, since moving the board after so long could cause bad connections.

So, without knowing what was the cause of the problem of the floundering guide post blocks, the proper operation of tape loading and unloading during Eject has been restored.

After replacing the leaky surface mount caps in the head amp, and an adjustment/alignment of the tape path, this machine may just operate again.

-- Cheers, WB .............

I have an EV-C3 which needs help. We'd love to get it running again sowe can view some of military time footage. Can you help? Or know a source of help. Thanks. Bill

There are a number of potential problems with this mostly due to age. What is the problem? Also, where are you located? There are some of us able to repair these, but a location is required.

Thanks, Dan

The older VHS decks had a "lighthouse" bulb sticking up into the cassette for end sensors at each side to detect the clear leader at the ends of the tape - what it does when the bulb blows depends on the firmware. A common symptom is; won't come out of standby.

Later ones had an LED on the post, which almost never failed.

No idea whether the 8mm has one - but I'd look to see.