Electronic Conquests!

Sharp VC-A5641 VCR failure:

Symptoms: Loads tape, and sometimes threads tape, but won't play, rewind, or fast forward.

This turned out to be a combination of two problems. Apparently the mode switch on these VCRs isn't very robust, and so the VCR can get confused about what it's supposed to be doing.

On this model, the mode switch is under the drive motor mounted in the upper right hand corner of the tape area. There are three screws that hold the entire assembly, so remove the rubber belts, unscrew the mounts, and the whole thing lifts right off. On the bottom you'll see a rotating round disc set into a housing, with a hole in it. This is the mode switch. The disc can be popped out ( I had to finesse it out with jewelry screwdrivers, but BE CAREFUL! it's delicate!) and the two tiny contacts cleaned, along with their brass tracks inside the housing.

Result: On my VCR, the tape loaded and threaded every time, but still would not play, rewind, or fast forward.

If all the mechanical parts appear to be operating but the tape reels do not move, the likely culprit is the capstan motor. Remove the bottom plate of the VCR, and you'll see a large metal pulley with a belt around it - this is the capstan motor. Sticking out from underneath it is a small printed circuit board, with a single capacitor, an IC, and a ribbon cable running from it. Look closely at the capacitor. On mine, the capacitor had leaked blue electrolyte all over the board, and it had eaten away the traces coming from the ribbon connector. Just find a refurbished motor, and replace the whole thing. It's held by three screws on the other side, where the capstan pokes though the body of the VCR. Pull the ribbon cable slowlllly upwards to disconnect it, push it in slowly to reconnect it on the new motor, and that fixed it for me as good as new, for about $13.

After the leaked electrolyte was cleaned, the corroded trace is clearly visible.


Dynatech VR-20

This is a lovely old VCR someone gave me....I miss the days of metal VCRs. It worked for a while, just fine, and then began making horrible squealing noises and failing. These VCRs run totally off rubber belts, that get old and crack, so get a replacement belt kit, take off the bottom of the VCR, and replace all the belts. That's about all you have to do, and it will work for another ten years. (For those of Þèê“who are asking "Why Bother?" - imagine you've got children over, or you're babysitting, and someone tries to put a peanut butter sandwich in the VCR like a tape. Or popcorn. (Both have happened to my mom.) Wouldn't you rather have the old one blown up than the new one? Also, it's just a shame to have these VCRs in a landfill when they work just fine. If you feel charitable, fix it and donate it. )


Hewlett - Packard Laserjet II and III Problems

Don't throw that laser printer away!!! It's easy and pretty cheap to fix!!

Problem areas:

AC power supply (50 Service Error)

LaserJet IIIsi prints blank pages only

LaserJet II / III paper jams at top of printer -

If the paper is making it past the fuser, and almost exits, this can be caused by two problems. One, the rubber feed roller at the very top is worn and needs to be replaced. This requires removal and some disassembly of the lid, but it's not too difficult. The other problem is caused by a bad fuser. When the fuser gets old, the hot roller becomes harder and harder to turn, and eventually the plastic gear wheels degrade from the heat. A gear wheel may strip, and since the upper roller is driven by the same gear train, it won't turn. The fix is a new fuser.

LaserJet III - control panel shows blocks and printer doesn't respond.

Rubber rollers - feed rollers, separation pad, solenoids (Paper won't feed. feeds more than one sheet or jams in various places)

Registration errors - printing is offset towards top of paper on first sheet

Upper and Lower fans (noisy buggers!)

More to come....


Parts sources:

VCR parts - http://www.diyvcrparts.com/

Printer Parts - http://www.printerworks.com/