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Datasette Repair/Calibration

robert_sissco

robert_sissco

Experienced Member
Joined
Oct 12, 2021
Messages
342
Location
Midwest U.S.A.
As part of a lot of software I purchased, a 1530 was included. My 3rd datasette, second 1530.

I cleared it up, tried to load some software, and it kept failing as if it was constantly finding files.

Took it apart to get to the read head, took a Q-tip, loosened the cotton, dripped in IPA and gave it a wipe down. Now it reads constantly, but the software fails to load. It just sits on the blank loading screen.

To test, I took my confirmed working 1530 down and ran the software through that, and I learned an important lesson...I suck that that game.

BUT, it loaded.

I remember one time seeing a cartridge on eBay to do datasette calibration, it would display the read signal and you would manipulate the potentiometer through the hole in the upper case just above the rewind button, but I cannot find it anymore.

Does anyone know where it can be acquired, either through the .CRT file or the cart itself?
 
DrAM19 said:
calibration cartridge for the datasette; never seen or heard of it.

Maybe you saw this one here, and can make a cassette
Click to expand...
It was basically a program that would show how the computer was receiving the audio files from the 1530 and you would adjust the potentiometer until it matched.
This may be it, I will copy it to a USB stick and get it moved to the Ultimate II+ to see if this is it.
 
Nice find ,it is also in my bookmarks now but since the mmc2iec era,i sold all of my floppy and cassette drives .Now i have plenty kung fu catrigdes and sd2iec but do you think i should buy a 1530 again? What about these new old stock found on bay?Were they original or what?
 
amijim said:
Nice find ,it is also in my bookmarks now but since the mmc2iec era,i sold all of my floppy and cassette drives .Now i have plenty kung fu catrigdes and sd2iec but do you think i should buy a 1530 again? What about these new old stock found on bay?Were they original or what?
Click to expand...
It is up to you. Personally I enjoy collecting new software released on cassette so the 1530 makes it possible to still play them, but I also have a 15302USB adaptor so I can backup tapes I have to .tap files that I would be able to load using such an adaptor, as well as an Ultimate II+ cart to backup/play cassette .tap files. I just have one datasette in a Commodore lot I purchased that could read data (it would display the programs is found on screen) but not load it properly. The speed seems compatible to my working 1530's. The big issue is that the program only works on PAL C64's, which isn't a big deal since I converted a C54 from NTSC to PAL in order to play the programs from across the pond, but I need to use a AV2HDMI converter box since both my 1701's are from the US so they don't play well together.
 
Hello , i just remembered i also have an easyflash3 as well but i kinda miss the days to wait and wait for the ghosts and goblins to load ,i mean how is my son supposed to learn what patience is.



robert_sissco said:
It is up to you. Personally I enjoy collecting new software released on cassette so the 1530 makes it possible to still play them, but I also have a 15302USB adaptor so I can backup tapes I have to .tap files that I would be able to load using such an adaptor, as well as an Ultimate II+ cart to backup/play cassette .tap files. I just have one datasette in a Commodore lot I purchased that could read data (it would display the programs is found on screen) but not load it properly. The speed seems compatible to my working 1530's. The big issue is that the program only works on PAL C64's, which isn't a big deal since I converted a C54 from NTSC to PAL in order to play the programs from across the pond, but I need to use a AV2HDMI converter box since both my 1701's are from the US so they don't play well together.
Click to expand...
 
My datasette had all the issues you can imagine:

- weak belts (noticeable on older tapes)
- dried out electrolytics
- connector so dirty / oxidised it required a pretty good scrubbing

Don't know if it was calibrated well as I screwdrivered it before I looked at the mentioned problems but it took me a while to get it working properly.

There's also Copy-H, it's supposed to be more precise for tape alignment but the display is not really intuitive..
csdb.dk

Copy-H

Commodore 64 Tool: Copy-H by Heinz Boehm. Released on 1986
csdb.dk csdb.dk
 
It's not a potentiometer, it's a screw that physically moves the read/write head.
There are a few ways to go about adjusting it.
There is no speed adjustment though. If the speed is off, it probably just needs new belts.
 
AndyG said:
Quick question : Have you replaced the belts ?
Click to expand...
No, I opened the case up to check those, and they were still in good condition, there were no cracks or slack in them when on the gears, but someone had cracked the loc-tite on the alignment screw, that is why I went there first. I plan on getting that fixed and then adding more loc-tite and going from there. Even if that does not fix it, it will at lease make me feel comfortable that that is aligned properly. It was sold as is, I bought the lot for the 1351 mouse (still in box, and an undamaged box at that), but I would like to get it to work at some point.
 
amijim said:
Hello , i just remembered i also have an easyflash3 as well but i kinda miss the days to wait and wait for the ghosts and goblins to load ,i mean how is my son supposed to learn what patience is.
Click to expand...
I have one as well, I keep it loaded with odd kernals so I can boot from that rather than needing eProms constantly. I would also love to but together a test kit like Adrian does in his Digital Basement, make it so much easier, but I need to dig it out. Moving at the moment and it have been packed for a few weeks, I had it for a while but my USB cord that would fit is broke and the one I got was a POS (I also have a MP3 player that uses it) so I actually both the Amazon branded cable that works for my MP3 player so I hope it will work for that as well once I have my n ew office setup.
 
I can't see how a software tool can help with a mechanical record-playback alignment issue with respect to a standard mechanical alignment of the record-playback Head.

If I were adjusting the head on one of these Datasette machines, I would seek to acquire a commercially recorded cassette tape and peak the recovered signal on that.

The reason being that the manufacturers of these commercial tapes had the heads in their record machines mechanically set up with alignment tapes that matched Commodores original machines. Though they would not be as good as a perfect alignment tape, but they are close enough.

The one reason, and only reason, why you would want the alignment of your machine to match the original mechanical alignment standard, is if you propose to run other people's tapes on you Datasette. If it is just for your own use your record playback on your own tapes will remain spot on in your own machine, it is just you won't be successfully able to share your tapes with anyone else or successfully playback commercial tapes.

One interesting thing I found while playing back commercial tapes on the Datasette: on the opposite side of the tape, from where it makes contact with the head, there is a small rectangle of latex sponge rubber glued to a phosphor bronze spring arm in the cassette housing. It is there to make sure that the tape is firmly applied to the tape head, yet not too much & provide too much friction.

The thing is that latex rubber, being a natural product decomposes. I found that on a number of tapes (even with perfect head alignment) the tape reads were patchy & often failed. , until I replaced that sponge rubber with new material. In other words, many of these vintage cassette tapes require this repair, if you are going to read them successfully, even if your Datasette is in perfect alignment with no other issues.
 
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Hugo Holden said:
I can't see how a software tool can help with a mechanical record-playback alignment issue with respect to a standard mechanical alignment of the record-playback Head.
Click to expand...
The software does a spectrum display of the data pulses coming from the cassette data line. You can use that to visually adjust for a peak in the frequency response.
You can see the software working in this clip Link
 
Hutch said:
The software does a spectrum display of the data pulses coming from the cassette data line. You can use that to visually adjust for a peak in the frequency response.
You can see the software working in this clip Link
Click to expand...
But that is hardly required, a simple RC HPF feeding the scope, or a low value coupling capacitor would do it if you wanted to peak the HF response, or by ear as noted.

What I was getting at though, is to set the head so it is in a compatible position with other tapes recorded on other machines requires a "test tape or alignment tape" that is at least close to commodore's standard, which is why the next best thing is to set it up on a commercially recorded cassette, not a recording from another datasette.
 
Hugo Holden said:
But that is hardly required, a simple RC HPF feeding the scope, or a low value coupling capacitor would do it if you wanted to peak the HF response, or by ear as noted.

What I was getting at though, is to set the head so it is in a compatible position with other tapes recorded on other machines requires a "test tape or alignment tape" that is at least close to commodore's standard, which is why the next best thing is to set it up on a commercially recorded cassette, not a recording from another datasette.
Click to expand...
I have been testing on tapes from TFW8B.com. They load on other datasette's without issue, so I know it is something isolated to this one.
 
robert_sissco said:
I have been testing on tapes from TFW8B.com. They load on other datasette's without issue, so I know it is something isolated to this one.
Click to expand...
It should be fairly easy to find the cause, looking with the scope at the amplified signal from the tape head and following that through to the output. If those tapes play in most other datasettes they must be fairly close to a standard alignment.
Though with relative alignment issues, you don't know for sure if the tapes from TFW8B load on ALL datasettes, they may on most though. A tape recorded with what would have been the exact standard alignment would likely load on the statistically higher number of datasettes, which would have a spread of alignment disparities around a central value that they were originally set at, at the factory using the standard tape.
It sounds like your problem is more significant than head alignment, possibly there is a fault in the head input amplifier area, but you would find that with the scope.
 
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Hugo Holden said:
It should be fairly easy to find the cause, looking with the scope at the amplified signal from the tape head and following that through to the output. If those tapes play in most other datasettes they must be fairly close to a standard alignment.
Though with relative alignment issues, you don't know for sure if the tapes from TFW8B load on ALL datasettes, they may on most though. A tape recorded with what would have been the exact standard alignment would likely load on the statistically higher number of datasettes, which would have a spread of alignment disparities around a central value that they were originally set at, at the factory using the standard tape.
It sounds like your problem is more significant than head alignment, possibly there is a fault in the head input amplifier area, but you would find that with the scope.
Click to expand...
Possibly, but as I lack a scope at the moment, and I noticed the loktite was already broken when I got in to check the belts, there is a possibility that this could also be the issue, and as I have a bottle of loktite and a PAL C64 to test with since the programs I found do not work with NTSC systems, this is the quicker, cheaper option, I just need to wait to unpack everything from my move to test the theory. I did clean the head with IPA and a demagnitizer I had for cassette players and that had the effect of at least the file names being read 5/5 times rather than 3/5 like it was before when I was testing.
 
Hugo Holden said:
Though with relative alignment issues, you don't know for sure if the tapes from TFW8B load on ALL datasettes, they may on most though. A tape recorded with what would have been the exact standard alignment would likely load on the statistically higher number of datasettes, which would have a spread of alignment disparities around a central value that they were originally set at, at the factory using the standard tape.
Click to expand...
This was also the same behavior with ALL TFW8B tapes I tried (I have 3 for the C64 and 8 for the VIC-20 and have tested all of them, and done most of the testing on the VIC-20 due to the time it takes to load the average program) and they all loaded fine with know two know working 1530's and even with my 1531 with the adaptor on both a C64 and my VIC-20's, and had the same behavior with the datasette in question.

I am load willing to trust these more that those from Commodore since these are new tapes made in a controlled setting, and while the Commodore published tapes may have been designed to work with the 1530's more reliability, most are 30-40 years old at this point, which raises questions about their current reliability in 2023.

If after confirming my head is properly aligned and working, I may need to go the scope route next, or before that maybe just get new belts to make sure those work, as that would be $10 v $100
 
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