lilley@boulder.Colorado.EDU (John Lilley) (04/11/89)
Anyone out there with an ST4051 hard drive may realize that they have reliability problems. In particular, some models will fail about every 8 months of normal use (just often enough for warranties to expire). I have discovered that the culprit 4 out of 5 times is a single chip that drives the spindle stepper. It is a 13-pin SIP flatpack, part #TDA1510. It looks like: ----------------------------------------------------------------- | | | | |__ __| \ TDA1500 / | | __/ \__ | | | | | | ----------------------------------------------------------------- | | | | | | | | | | | | | / | / | / | / | / | / | / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Every other pin is staggerred upwards. This part costs about $3 and can be obtained from Hamilton-Avnet's Texas distributor. It is made by Signetics. Much better than paying $150 and up! This chip is not always the problem, but you can usually tell if it is, by listening to the drive when it powers up. Plug in the power (no other cables are necessary), and listen. If you hear a faint "click" from the drive, and nothing else, then this chip is probably to blame. If the drive spins up, then this chip is definitly NOT to blame (the drive cannot spin without it). After determining that this chip is the problem, desolder it with braid or a desoldering station, and solder in the new chip. MAKE SURE that you place an insulator between the chip and the PC board or it may not work, as the original TDA1510 used by Seagate (Hitachi) is different than the one I mentioned (Signetics). If this fixes the problem, you should be able to use your disk again WITH NO DATA LOSS! You may need to replace this chip again, so buy two for good measure..... This is a great way to get a cheap 40M, 40ms drive if you can find a busted ST4051. If anyone is skittish about soldering on their drive, I might be able to help out for a reasonable fee (maybe $50). No guarantees! Interestingly enough, the chip is a 12W audio amplifier chip. I guess it almost did the job of a motor controller..... P.S. SPECIAL THANKS to J.B. Technologies for (A) Telling me not to bother having them fix it cause it would just break again, and (B) Telling me what was wrong with the drive and what to replace. P.S. NO THANKS to Seagate for their zero help :-( I would appreciate comments from anyone who tries it. --john lilley (lilley@boulder.colorado.edu)
caf@omen.UUCP (Chuck Forsberg WA7KGX) (04/17/89)
In article <8059@boulder.Colorado.EDU> lilley@boulder.Colorado.EDU (John Lilley) writes:
I have a 4051 that won't start up unless it is 1) warm or 2) is jiggled
about its rotational axiz to help it get going. Once it's spinning
all is well, but a few hours of power-down and it won't start. Is
this the tesult of a weak motor controller chip or bad lubrication?
Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf
Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ
Omen Technology Inc "The High Reliability Software"
17505-V NW Sauvie IS RD Portland OR 97231 503-621-3406
TeleGodzilla:621-3746 FAX:621-3735 CIS:70007,2304 Genie:CAF