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1530 "SAVE" LED normal behaviour?

Posted: Wed Mar 27, 2019 2:14 am
by JCS
Hello! It's my first post.

I'm fixing up a not-quite-working 1530 datasette for my C64. Unfortunately, I don't have (and have never used) a properly functioning datasette to compare it to.

I have a specific question that will help me with my troubleshooting:
On a properly functioning unit, under what conditions does the "SAVE" LED turn on, and when does it turn off?

For example, is it always on when the datasette has power? Or, only when a 'motor' signal is sent? Or only when recording? or... ?

If it matters, mine is a later-model ('square' or 'fat') 1530 with the LED on the left, just above the record button. (That's apparently rare? I see many more pictures online of models with the LED on the right, below the counter. But I digress.)

So, if anyone has experience with a datasette with an LED, a quick description of when the LED normally turns on and off would be really helpful. Thanks!

Re: 1530 "SAVE" LED normal behaviour?

Posted: Fri Apr 19, 2019 2:08 am
by JCS
I opened the device up again to change the belts, and when I put it all back together, somehow the electronics all started behaving properly! I'm not even sure what I did, but at least now the datassette works. It looks like I'll end up answering my own question, here. I guess not many people use the datassette anymore, and of course only a subset of those have one with an LED.

In case anyone else is ever repairing a 1531 and wants to know how the LED is supposed to work (because I found no info on this when I was searching, I'll put it out there now):

The LED only ever turns on during recording. When the user begins a SAVE operation and then presses both record and play, the computer sends power to the datassette's motor and this also lights the LED. When the SAVE operation is done, the motor stops and the LED goes off, even though the record and play buttons are still held down mechanically (until the user clicks 'stop'). During other operations of the motor (Read/play, FF, REW) the LED does not go on.

This is much different than when I first plugged it in and the light went on right away, then went OFF when I started to record... something must have been shorted (and I'm lucky nothing got fried).

Re: 1530 "SAVE" LED normal behaviour?

Posted: Fri Apr 19, 2019 3:32 pm
by eslapion
JCS wrote:
Wed Mar 27, 2019 2:14 am
If it matters, mine is a later-model ('square' or 'fat') 1530 with the LED on the left, just above the record button. (That's apparently rare? I see many more pictures online of models with the LED on the right, below the counter. But I digress.)
The 'square' model is actually the oldest which was sold in the times of PET computers.

https://en.wikipedia.org/wiki/Commodore_Datasette
So, if anyone has experience with a datasette with an LED, a quick description of when the LED normally turns on and off would be really helpful. Thanks!
What do you want to know exactly?
This is much different than when I first plugged it in and the light went on right away, then went OFF when I started to record...
Ha! That's the actual problem.

The schematics for various models are here:
http://www.zimmers.net/anonftp/pub/cbm/ ... index.html

Re: 1530 "SAVE" LED normal behaviour?

Posted: Fri Apr 19, 2019 7:43 pm
by JCS
eslapion wrote:
Fri Apr 19, 2019 3:32 pm
What do you want to know exactly?
I'm sorry if I didn't make it clear. What I wanted to know was:
JCS wrote:
Wed Mar 27, 2019 2:14 am
On a properly functioning unit, under what conditions does the "SAVE" LED turn on, and when does it turn off?

For example, is it always on when the datasette has power? Or, only when a 'motor' signal is sent? Or only when recording? or... ?
By my second post, I had found the answer:
JCS wrote:
Fri Apr 19, 2019 2:08 am
The LED only ever turns on during recording. When the user begins a SAVE operation and then presses both record and play, the computer sends power to the datassette's motor and this also lights the LED. When the SAVE operation is done, the motor stops and the LED goes off, even though the record and play buttons are still held down mechanically (until the user clicks 'stop'). During other operations of the motor (Read/play, FF, REW) the LED does not go on.
Had I known that ahead of time I'd have known right away that there was a problem when the light came on as soon as I powered up the system, but I just couldn't find a description of the proper LED behaviour anywhere online.

Thanks for the link to the schematics! That might help in the future if the unit gives me any more problems. I wonder if it describes the LED in there (I haven't read them, seeing as I've already solved it, but I'll definitely want that bookmarked for the future.)

Yeah, the 'square' model is an earlier one (the used one I bought came with its original manual, which mentioned only the PET and VIC-20... no C64 yet). Most of the 'square' ones I see online have the LED on the right (as do all three in the pictures under the 'models' heading on the wiki page you linked to). Mine happens to have the LED on the left side of the unit (like the top picture on that Wiki page). I doubt that detail matters as to the LED's behaviour, though.

Anyway, thanks for the input and especially for that schematics link! Cheers.