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Commodore Pet acquisitions

D

DarthKur

Experienced Member
Joined
Jan 2, 2007
Messages
171
Location
Western North Carolina
The other week I came across a place that had a few Commodore items for sale. There were a couple FDD's, a 1541 and 1571, plus a C64c and a 128d. Those were fine but what caught my attention was the model 8032 Pet and 8250 dual FDD sitting there across from the rest of the stuff. The Pet fired up just fine and the FDD powered on but there was no IEEE 488 cable to connect the two. It was in my financial grasp (i.e. cheep) so I bought them. Later on it turns out that there were two more of these combo's in the back. I couldn't resist but snag them as well even though one of the Pet's was obviously defective and missing a couple keys. Plus one of the FDD units had a big sign taped to it stating that it had the "5 blink error". So I figured that was sure not to work right but might be an easy fix. Oddly enough the drive with the sign taped to it is the only on that functions correctly. One of the other dual drives has the L.E.D.'s blink 5 times when connected. So it was a mislabel. :p
I was able to connect the Pet and FDD solely thanks to Anders on the boards here that answered my wanted add. Again, a huge thank you to you Anders.
Here are a few pics of the functioning combo. I'll post pics of the others later.

Pet1.jpg


Pet2.jpg


Pet3.jpg
 
Nice.

According to the service manual, five blinks means there is an error with the zeropage memory, either the 6530 (likely) or 6502 (less likely I think).
http://www.zimmers.net/anonftp/pub/cbm/schematics/drives/old/8050/index.html

I don't know what kind of media you're using, but I'd recommend 96 tpi soft sectored, a.k.a. QD. The 8050 and 8250 drives will format 48 tpi disks too, but they may quickly become unreliable depending on which brand of floppy disks you use. The 1.2 MB HD ones clearly are out of the question.
 
The disk I used in my tests is a Verbatim SS/DD. I don't have any QD's. I just checked Ebay and there are none to be had. I just read on one of the various Pet websites that the QD's are quite hard to come by. :(
 
Quite, but far from impossible. Even our friends at Athana still produces or at least sells QD certified floppy disks. Fresh DD floppies from a good brand may work just as well, as it is said the difference betweeen them was that those batches not living up to QD capacity were sold as DD, or that even floppy disk manufacturers on purpose labeled them as DD to not confuse buyers in a time when the relatively few systems using 96 tpi floppy disks had become extinct.
 
carlsson said:
Quite, but far from impossible. Even our friends at Athana still produces or at least sells QD certified floppy disks. Fresh DD floppies from a good brand may work just as well, as it is said the difference between them was that those batches not living up to QD capacity were sold as DD, or that even floppy disk manufacturers on purpose labeled them as DD to not confuse buyers in a time when the relatively few systems using 96 tpi floppy disks had become extinct.
Click to expand...

That's quite interesting. I never knew that. So with them being so similar there is at least a fair chance of success then. I just checked Athana and the do list a few 96 tpi disk's:
5.25 Inch Diskettes DD (Double Sided, Double Density), Unformatted, 96 TPI (Soft Sector), ATHANA Box


47-8801

5.25 Inch Floppy Disks HD (High Density, Double Sided) Diskettes, Unformatted, 96 TPI (Soft Sector), ATHANA Box


47-9501

5.25 Inch Floppy Disks HD (High Density, Double Sided), Unformatted, 96 TPI (Soft Sector), Plain White Box


47-9501G

So would that be the HD 96 tpi ones or the DD ones that would be the best to work with the 8250? I notice they no longer list their prices. Usually when a business does that it means the prices are in the higher range. Still, it would be good to get a least a couple boxes of disk's that fit the exact specs of the hardware.
Thanks for the links to the tech guide you previously linked to. I can't seem to find either the 8032 Users Manual or a Basic 4.0 guide book anywhere online. Have you any idea where of where they might be found?
 
Awesome find, Darthkur. There was a post on craigslist around 6 months ago or so somewhat nearby for an 8032 that had "issues" but it was free. Someone else beat me to the punch and snagged it :cry:
 
You need 96 tpi DD. The 96 tpi HD ones are for IBM PC 1.2 MB drives and pretty much nothing else. It won't work at all to use those; I've tried. ;-)
 
It certainly can't hurt to use 96TPI QD disks if you can find some, but I've never had any problems using good quality ordinary DS/DD disks in my 8050s. YMMV though...

m
 
But to be anal about it, some people claim 96 tpi ain't enough either, that you really need special 100 tpi floppy disks to get data stored reliably. In any case, the drive formats 77 tracks over the surface, whether it is one inch or not.
 
Regarding the disks, last I checked about 5 months ago, the 360K disks ran about $10 a box, and the 720's and 1.2MB disks ran $11.

--Jack
 
willowmoon93 said:
Awesome find, Darthkur. There was a post on craigslist around 6 months ago or so somewhat nearby for an 8032 that had "issues" but it was free. Someone else beat me to the punch and snagged it :cry:
Click to expand...

Sorry to hear that. It's so frustrating to find something like that so close just to discover it's already gone.

80sFreak said:
billdeg and I have both used 48 tpi DS/DD disks in 8050s, 8250s, and SFD-1001s with no problems...

Cheers,

80sFreak
Click to expand...

That's definitely good to hear. It would be a shame to have the drive units and not be able to make reliable use of them.

carlsson said:
But to be anal about it, some people claim 96 tpi ain't enough either, that you really need special 100 tpi floppy disks to get data stored reliably. In any case, the drive formats 77 tracks over the surface, whether it is one inch or not.
Click to expand...

100? Was there ever such a thing? If so were they made specifically for this types of FDD's?

Yzzerdd said:
Regarding the disks, last I checked about 5 months ago, the 360K disks ran about $10 a box, and the 720's and 1.2MB disks ran $11.

--Jack
Click to expand...

While not exactly economical that's, at least, not horribly exorbitant.
 
Yep, a couple of brands in the early 1980's made and marketed 100 tpi floppy disks. Some claim it makes a significant difference, I think it is mostly a marketing gimmick. The floppy drive heads supposedly have that resolution but as I wrote the drive only formats 77 tracks.

On a soft sectored disk, the tracks per inch measurement would to me just indicate the maximum level of detail guaranteed from the manufacturer, not that any misalignment may occur. The Commodore 1541, early Apple II and other floppy disks format 35 tracks on a 48 tpi disk, later on the more common 40 tracks. If there was a serious issue with tpi-ness, I'd expect it occur to those formats too unless the heads also has the resolution to read and write in 48 different positions per inch, effectively a number of half-tracks.
 
I'm not quite clear on what you're trying to say, Anders...

I think that whether the disk is hard- or soft-sectored or how many of the available tracks are actually formatted and used doesn't have much to do with the TPI question. The issue is the head width, which is obviously narrower on the 96 and 100 TPI drives; if there's a tiny bad spot on the disk then the narrow head is more likely to misread it, while the wider head may get enough flux from the area beside it to read correctly.

Unlike the 96TPI 1.2M HD disks which use a different material, AFAIK the 96TPI DS/QD disks used the same material as DS/DD disks, but they were actually tested and certified; most of the newer good quality disks seem to all be certified anyway. Yeah, I'd say that 100TPI disks were a marketing device.

As I said, in my and many others' experience you can use pretty well any kind of diskettes in an 8x50 (except for HD of course), even hard sector, as long as they're good quality. But back up any important data no matter what...

m
 
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