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SUCCESS
December 28th, 2009, 05:17 PM
Hi people,

Today, apart from my defective 64 =((((((( I noticed a failure in the C64 from my brother (a Drean Commodore) which I've finished two weeks ago.
We put a working 1541 and after typing LOAD "$",8, the C64 puts:
"SEARCHING FOR $", but the red led doesn't turn on. Also, them motor doesn't spin. The C64 hangs and waits forever ....
The drive is fully working, tested with a good 64 and also using the XE1541 cable ... so it can't be the drive. The IEC cable is also fully working.
The C64 resets the drive as expected when it's powered on.

What is going on with this ?????. Can you help me ?. Could be a CIA ?.

Thanks for reading !!!

Pedro.

carlsson
December 29th, 2009, 03:25 AM
Yes, it sounds likely to be a broken 6526 CIA. If they are socketed you could try to swap or replace them.

digger
December 29th, 2009, 05:42 AM
the C64 puts: "SEARCHING FOR $"

Right now I could give in to temptation and respond with easy joke referring to the current state of the world economy, but I'll try to restrain myself... :lol:

SUCCESS
December 29th, 2009, 07:37 AM
Right now I could give in to temptation and respond with easy joke referring to the current state of the world economy, but I'll try to restrain myself... :lol:

:D:D:D:D:D:D:D

That's why the C64 hanged ....

geoffm3
January 5th, 2010, 08:00 AM
Yes, it sounds likely to be a broken 6526 CIA. If they are socketed you could try to swap or replace them.

Agreed... this sounds like the best place to start.

SUCCESS
January 11th, 2010, 07:58 AM
Lets update

Changed the two CIA's (although only one is used in the serial bus).
Checked al PCB traced from CIA to DIN. Checked al data lines from MPU to CIAS. Also the adrress BUS (A0-A3).
Also the lines coming from the 74LS139 adrress decoder that selects the CIAS.
Also the protection diodes used in the bus lines.

But nothing to do .... Just SEARCHING FOR $.
If I turn off the 1541, the 64 writes "DEVICE NOT PRESENT". Also, the drives is reset by the 64.
In only one case, a command tuned the red ligth on, but the 64 went stuck
I put LOAD"*",8,1. Not always, but sometimes this turn the red ligth on. But nothing else happens.

Commands like PRINT#15,"I" also hangs, but not OPEN15,8,15

Any clue to help this 64 ?.

Many thanks for reading !!!.

Pedro.

geoffm3
January 14th, 2010, 10:09 AM
Did you try swapping the VIAs in the 1541?

SUCCESS
January 14th, 2010, 03:40 PM
Did you try swapping the VIAs in the 1541?

Nop, but the drive works fine with other two C64 I had ....

Pedro

SUCCESS
January 17th, 2010, 03:01 PM
Solved:

There was a short in the botton of the socket I installed for the 7406N. The short was on the ATN line.

Pedro