G'day Bill,



      I dunno if you'll be able to help or not..  but I've currently

got a VCR in the workshop that I've dubbed "the machine from hell".



Its a Philips VR6740 (similar to the Sharp VC486), and for reasons

unknown it keeps blowing the capstan drive IC (TA7267).



So far it has blown about 5 of them (over a 3 week period). It has also

blown 2 micro's in the same timeframe.



It doesn't appear to be temperature sensitive and the chips are running

cool.. I've even gone as far as mounting a thermal fuse on the chip

justincase whatever the cause is causes a momentary heat build up. The

chip still failed with the thermal fuse intact. I've also placed a

100ma ICP fuse in series with the capstan motor (which is drawing

approx 50ma).. again the chip has failed with this fuse intact.. IOW

its doesn't appear to be blowing from either excess current or heat.



There are no warning signs as to when its gunna blow - in fact it has

gone for up to a week running 14hrs a day without a problem (other

times it'll blow in under an hour).  You can be watching the playback

picture then it just 'pauses' for a second as the chip fails, then the

syscon shuts the machine down.



I've replaced most of the caps in the power supply (because there was a

*little* bit of ripple on the 12v line)..  The ripple has now gone, but

the chip is still failing.



Any ideas at all ?   I'm willing to clutch at any straws at this stage.

The machine is a comeback, a week after the original repair (which

was no eject, caused by slipping idler tyre) so I can't 'easily' just

wash my hands at it and place it in the 'too hard' or

'uneconomical to repair' basket.



So far it has cost me over $100 more in parts than I charged for the

original repair..  the customer is quite agro and is implying that *I*

put the fault on the machine and that he wants it fixed at my expense

(whats new?). I don't mind wearing this loss IF I can get the machine

working reliably, but it has me stumped.  My only other alternative is

to give him a full refund, leaving myself almost $150 out of pocket,

plus about 2days labour down the drain..  Still.. this may be the

cheapest way out for me. :-(



Cheers,

Rod



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