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Tandon Thinline 8" drive question

T

Tibs

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Dec 10, 2016
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So, I've got what is more than likely super crudy heads from this Wabash disk I got my hands on.

I have an unused 8" cleaning disk, and before cleaning I couldn't get past Track 0 sector 4, then cleaned it a bit (30 seconds) and got to sector 5, cleaned again, sector 10, again now sector 16, then cleaned again and it got to sector 20. Now, I'm fine pulling the drive and cleaning it, but before I get to that point do you think its just crud from the floppy? Or something worse like write current? I'm doing the whole pattern thing with 4-5 sectors per attempt added LOL.

I know how old these things are, and it was working before this happened, I think :). TRSDOS 2.0A and thin lines is a challenge in speed before the drive spins down.

Reality check before I get too deep in this.

TRSDOS 2.0A doesn't care about double sided and will just format side 1, 26 sectors per track, correct? I want to be sure I dont have a buggered up head.
 
I never liked the Tandon 8" drives. Check the output of the 12V regulator on the drive board--the capacitor on the output of that likes to dry out. Make sure you're really providing enough +24V for it.

Open things up and gently clean the heads with a swab and some isopropanol.

Bitsavers has the maintenance manual for it.
 
Are there any other thin 8" drives that will work in a Model 12/16B/6000 without cutting the bezel?
 
Thanks, Chuck. The SA810 might fit without cutting the bezel, but the YD-180 definitely wouldn't work.

I'll have to compare the drawings for the SA810 to the TM-848 to see if the lever is in the same place.
 
You should be using TRSDOS 2.0B (or 2.0D) with the TM-848. 2.0B handles the timing needed to support the off-and-on thin line drives. 2.0A expects the constantly running Shugart (or TPI) drives in the Model II and will not run properly on the 12.

TM-848s are a pain to clean properly, especially given that you have to open up the Model 12 to get good access to the drive. Opening up a 12 is a whole other pain.

If you're going to use the machine other than as a show piece with the occasional power-up, then I highly suggest switching to using a floppy emulator like the HxC. When I first started playing with the big Tandys the TM-848 almost made me swear off the platform. Save the TM-848 for special occasions. They don't make them like that anymore...thank God. :)
 
While rebuilding my Model 6000 I had the idea that once it's all tested and working I might connect the cable for the internal drives to the external drive connector and then run a cable from the internal drive connector externally so I can use whatever I need (real drive or floppy emulator) as drives 0 and 1 and have the internal drives as drives 2 and 3 (with the jumpers changed).

I'm not finished with the rebuild so I haven't verified if I can route the cables that way when it's completely assembled. It might require making a new internal drive cable.
 
I had some old Wabash disks (5.25") and when I tried to use them the head just scraped the magnetic coating off, leaving a thin track of transparant disk!

Floppy drive then problematic.

I suspect that it's not so much goo on the head, more likely that the shaving off the disk has got somewhere it ought not to have. Like interfering with the stepping. That sounds more like what you've got. You need to get inside and hunt the bits.

Of ALL the 5.25" disks I've got, the Wabash ones are the ONLY ones doing anything untoward. They were considered 'good' when I got them (early 80s). Piles of cheap no-name disks are still working perfectly!

Geoff
 
I've discussed Wabash-branded floppies several times here. They were terrible when they were only 10 years old.

I have a way to handle them, but it's not easy. Basically, I coat the disks with a lubricant after baking them. You have to be desperate. Unfortunately, Wabash sold to some "white box" resellers also. "Wright Line" comes to mind.

The last time I fouled a drive head with a Wabash floppy, it took acetone to get it completely clean. Perc would also work--but be careful; either affects plastic parts.
 
I have to say that I haven't had a lot of issues with TM-848, even back in the day when they were actually used regularly by clients for backup. Note that there are two versions, the original mostly discrete TTL IC belt-driven TM-848 and the improved later MSI IC direct-drive TM-848E version.
 
Thanks all, yeah I know about the TRSDOS thing, I was mainly just testing out a few things while waiting on the boards. Its what I had at the time. Boards should be here tomorrow then I can use the emulator and make the proper diskettes.

I did pull it apart and check the capacitor, it looked like crap (and I loved them using a radial in place of the axial silkscreen). Changed it but still getting the issue. It can read a properly formatted disk fine, just cant write good.

I was super gentle with cleaning, but if I cant get it to work, I might do the acetone method. Went ahead and lubricated all the moving parts while in there, and had to adjust the disk change/lever switch thing.

Either the circuit that writes is defective or the head still has some crap in it, or the adjustment of the arm per the troubleshooting section. I've seen this before after getting a Wabash disk in a drive, and yes it did become clear where the head hit it, and it takes a TON of patience.

There could just be a little shaving inside the head causing it not to write sufficiently.
 
Dirty head, really dirty head.

Of course the drive spins down after 14 tracks (like expected on 2.0a) but it worked after a few good runs with the cleaning disk.

I was just about to get the acetone out and it hit 26 sectors and started stepping.

Thank you guys for the help, and Frank and co on the capacitor. I changed the other one as well just to be safe.
 
Toldja that Wabash floppies were bad news.

Oddly, 1/2" Wabash tape appears to be just fine, from the stuff I've seen. Must be the sycamores and the breath of new-mown hay.

Add to your list some single-sided Radio Shack-branded 8" floppies. There was a really bad batch (some think it was warehouse storage conditions) that is just as bad as the Wabash stuff.
 
Chuck(G) said:
Toldja that Wabash floppies were bad news.

Oddly, 1/2" Wabash tape appears to be just fine, from the stuff I've seen. Must be the sycamores and the breath of new-mown hay.

Add to your list some single-sided Radio Shack-branded 8" floppies. There was a really bad batch (some think it was warehouse storage conditions) that is just as bad as the Wabash stuff.
Click to expand...

LOL I called you Frank...sorry I meant Chuck. Yeah, the double sided Wabash were in great condition, it was the single sided single density ones that I should have known better....I went back and checked the thread you and several others talked about these in and I've book marked it.
 
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