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View Full Version : Filled Anyone able to offer advice / REPAIR a Commodore 1541-II disk drive please?



baz67
22nd July 2015, 17:37
Afternoon, folks.
Just tried firing up a C-64C and 1541-II floppy drive and we are NOT cooking on gas.
The drive powers up - power and drive LEDs light up at the front but the drive just continuously spins... and doesn;t want to stop.
Have tried turning off/on; removed drive cover - checked the 3 mini plugs - pulled them off, placed them back on, give it all a good blow, removed further screws and lifted Chinon 5.25" drive assembly to see if there was anything else 'obvious', eg chips not seated properly - gave them all a wee push for good measure...
Put it all back together and SAME OLD... drive mechanism just spins up and keeps on spinning, doesn't stop, so clearly there's something wrong with its start-up routine.

Anyone else out there in Amibay land able to please pass on some advice/offer a repair as I'm new to the CBM scene being an ardent Atarian, Acorn nut and Orician (but don;t hold that against me!)

Cheers, guys.

ANDY

roy_bates
22nd July 2015, 18:34
does the drive initialize without the computer connected?

baz67
22nd July 2015, 18:42
No, Roy - does the self-same whether connected to the C64 or on its own - just spins away merrily... never stopping.
Thanks.
ANDY

Sardine
22nd July 2015, 19:05
thecorfiot repairs these and has the genuine calibration / alignment disks.

SaviorX
22nd July 2015, 19:23
http://personalpages.tds.net/~rcarlsen/cbm/1541/1541chip.txt

(http://personalpages.tds.net/~rcarlsen/cbm/1541/1541chip.txt)UC2 6522 VIA (MOTOR CONTROL INTERFACE)
When drive powered up, red LED stays on and spindle motor runs
continuously. Check also UA1, UB4, UC4, UC5, UC6, UD3, and UD5.

UC4 6502 MPU
When drive powered up, red LED stays on and spindle motor runs
continuously. Check also UA1, UB4, UC2, UC5, UC6, UD3, and UD5.

UB4 901229-03 or -05 DOS ROM 2
When drive powered up, red LED stays on and spindle motor runs
continuously. DOS ROM is a common failure. Check also UA1, UC2, UC4,
UC5, UC6, UD3, and UD5.

UC5 74LS04 (74LS14) LOGIC
When drive powered up, red LED stays on and spindle motor runs
continuously. Check also UA1, UB4, UC2, UC4, UC6, UD3, and UD5.

UC6 74LS00 LOGIC
When drive powered up, red LED stays on and spindle motor runs
continuously. Check also UA1, UB4, UC2, UC4, UC5, UD3, and UD5.

(a few other possibilities listed as well)
(http://personalpages.tds.net/~rcarlsen/cbm/1541/1541chip.txt)

baz67
22nd July 2015, 19:27
Thanks for the pointers/tips, Sardine/SaviorX.
I'll drop thecorfiot a message and see what he recommends.
Cheers, folks - much appreciated.
ANDY

Sardine
22nd July 2015, 20:36
thecorfiot's service and repairs are excellent.

I'm very happy with my 1541.

baz67
22nd July 2015, 20:41
Thanks, fellas.
Thecorfiot is indeed a 1st class guy and has already PMd me with a costing... unfortunately, finances being tight, I've decided to sell the whole C64 caboodle and will list the 1541-II as spares/repair on here for someone else to get their teeth into it.
Cheers - do appreciate the advice and pointers this community gives - brilliant, folks.
ANDY

Retro-Protect
22nd July 2015, 21:12
If it keeps spinning it's usually Dos ROM fault. This has a socket in 1541 so easy to test with a working chip. I assume the same in 1541-II?

roy_bates
22nd July 2015, 21:25
no,its not the same rom chip in the 1541 and 1541 II

bas can confirm that.

TheCorfiot
23rd July 2015, 00:11
It's different firmware and also a different type of Rom :)

baz67
23rd July 2015, 11:34
Thanking you, fellas, for all of your input on this one.
Your knowledge base never fails to amaze/impress me.
Unfortunately, I have no spare chips etc and alas haven't the spare cash either, now, to go ahead with a repair so I'll be listing on here later the drive for sale with its box and all connections.
I do again thank you all for your help and suggestions.
Best wishes,
BAZ67

demolition
23rd July 2015, 15:09
I have seen this exact issue a couple of times - both were caused by a bad PSU (and the 1541-II PSUs are not the most reliable). If the 5V line is insufficient, the logic in the drive cannot initialize and it just keeps spinning. So if you have another PSU, try that first.

baz67
23rd July 2015, 16:17
Hey Demolition,
Thanks once more for what sounds a top tip... regrettably, I have no spare 5v PSU for this drive and I;ve no buddies living nearby with any of this Commodore 8bit hardware for them to lend a hand.
I've just discovered the box (thereby the drive within?) and software bundled with it comes complete with GEOS desktop 1.5 operating system... maybe this will make it a desirable drive to own if someone else will undertake the testing/repairs?
Anyhow, over to you guys and from my disappointment, I hope the price makes it into a bargain for someone...
Cheers, all.
BAZ67

roy_bates
4th August 2015, 22:30
i dont know if anyone would be interested,but,i bought this drive:)

it now works fine,and ive fitted jiffydos to it:) probably use it with my breadbox 64,so alls good.

it had faulty firmware,and bad sram.