CBM 4032 can't read from tapes... any help?

[asbesto]

Hi there,

our CBM 4032 can save programs into tape, but can never read them.

We used an aligned C2N cassette tape recorder, previously tested with a Commodore 64...

Any idea? I red somewhere that tapes are a real problem on old PET's ...

 

[carlsson]

What is the age and quality of the tapes you are using? Did you try the same experiment with a C64 or similar computer, so you have ruled out a malfunctioning C2N and ditto about the actual tape?

 

[asbesto]

Yes, I said before that we used a C2N tape and a cassette previously tested on a C64 and they are perfectly working!

 

[dabone]

Make sure to clean the tape connector on the mother board. I use a eraser. Make sure
To clean both sides.

Later,
dabone

 

[jac_goudsmit]

I don't remember ever opening a C2N but I bet it has at least one rubber belt. When those get old, they get soft and/or sticky and/or stretchy. That will undoubtedly cause tape speed fluctuations during recording as well as playback that the computer can't deal with.

===Jac

 

[carlsson]

Which chip handles the C2N, is that the 6522 or one of the 6520's? Perhaps the chip in question has a partial fault so it would only work on output but not on input.

 

[tezza]

Also check the pins on the cassette drive cable. Sometimes these can be damaged or pushed up too far into the plastic housing hence not making the correct connection to the card edge.

 

[jac_goudsmit]

A quick (re)study of this page tells me that the cassette ports are controlled by the 6522 and one of the 6520s (the same one as the keyboard).

Try connecting the cassette drive to the other port (inside the computer) and check if it works from there (I think the command is LOAD"",2). That should tell you if the problem is (likely) in the cassette drive. You can also try swapping the two 6520 chips to see if it makes a difference.

Personally, I would connect a small speaker to the read input (with a series resistor to limit the current, I'd probably use 100 or 220 ohms), and listen if it "sounds right". Because of age, the cassette mechanics are still my #1 suspect.

===Jac

 

[MikeS]

... Because of age, the cassette mechanics are still my #1 suspect.

===Jac

I second that; the drive belt's almost certainly stretched or turned to goo.

Do we actually know that it can save a program, i.e. can it be read/loaded on another computer?

 

[carlsson]

Well, I read asbesto's reply as they have recently used the exact same C2N on a C64 and were able to both save and load programs on that one.

 

[MikeS]

Well, I read asbesto's reply as they have recently used the exact same C2N on a C64 and were able to both save and load programs on that one.

Yes, but even if that's true that doesn't tell us whether the 4032 is actually saving correctly.

 

[asbesto]

...but this exclude any C2N belt fault

 

[MikeS]

...but this exclude any C2N belt fault

Perhaps, but not necessarily; what worked a week ago may not be working today.

It would still be good to know whether the PET can read a tape from another machine and whether another machine can read a tape from the PET.