Re: HP 7970B Capstan?

2017-09-08 Thread Chuck Guzis via cctalk
On 09/08/2017 07:24 AM, Jay Jaeger via cctalk wrote: > On an IBM 1410 (at least - but I suspect this was likely widely true), > tape marks were *always* EVEN parity, 0x0F (Bits 8421), even on an odd > parity tape. Oh, I know--but remember that I was reading a 7-track tape in a 9-track drive.

Re: HP 7970B Capstan?

2017-09-08 Thread Jay Jaeger via cctalk
On 9/7/2017 9:35 PM, Chuck Guzis via cctalk wrote: > On 09/07/2017 07:18 PM, Jon Elson wrote: > >> Ah, well, I can see why a 7 track tape won't read well on a 9-track drive! > > I was a bit puzzled at why a tapemark would read as 135 (hex). Sigh--at > least the parity is correct. > > --Chuck

Re: HP 7970B Capstan?

2017-09-07 Thread Chuck Guzis via cctalk
On 09/07/2017 07:18 PM, Jon Elson wrote: > Ah, well, I can see why a 7 track tape won't read well on a 9-track drive! I was a bit puzzled at why a tapemark would read as 135 (hex). Sigh--at least the parity is correct. --Chuck

Re: HP 7970B Capstan?

2017-09-07 Thread Jon Elson via cctalk
On 09/07/2017 02:24 PM, Chuck Guzis via cctalk wrote: On 09/07/2017 09:32 AM, Al Kossow via cctalk wrote: The problem you're fighting is things are just a little marginal at 800 ? As I just mentioned to Al in an offlist email, it turns out that the stack of tapes labeled "800 NRZ 9 track"

Re: HP 7970B Capstan?

2017-09-07 Thread Chuck Guzis via cctalk
On 09/07/2017 09:32 AM, Al Kossow via cctalk wrote: > The problem you're fighting is things are just a little marginal at 800 ? As I just mentioned to Al in an offlist email, it turns out that the stack of tapes labeled "800 NRZ 9 track" are, in fact, 7 track. Kyread doesn't lie. Argh. Time

Re: HP 7970B Capstan?

2017-09-07 Thread Jon Elson via cctalk
On 09/06/2017 10:09 PM, Chuck Guzis via cctalk wrote: Here's a thought--can skew be adjusted by writing,a block of data in a forward direction, then reading it in reverse? Nope, it will always show perfect skew. What you COULD do, is take the tape off the reel and turn it around. THEN, any

Re: HP 7970B Capstan?

2017-09-07 Thread Al Kossow via cctalk
On 9/6/17 9:20 PM, Chuck Guzis via cctalk wrote: > If you could spare it for a week or so, I'd be grateful. On the other > hand, my MCU setup for the drive works great--it reads a tape and > stashes the data as a .TAP file on an SD card. The problem you're fighting is things are just a little

Re: HP 7970B Capstan?

2017-09-06 Thread Chuck Guzis via cctalk
On 09/06/2017 08:14 PM, Al Kossow via cctalk wrote: > I could mail you a skew tape. > > On 9/6/17 8:09 PM, Chuck Guzis via cctalk wrote: > >> I'm just scratching around looking for ideas. If you could spare it for a week or so, I'd be grateful. On the other hand, my MCU setup for the drive

Re: HP 7970B Capstan?

2017-09-06 Thread Al Kossow via cctalk
I could mail you a skew tape. On 9/6/17 8:09 PM, Chuck Guzis via cctalk wrote: > I'm just scratching around looking for ideas.

Re: HP 7970B Capstan?

2017-09-06 Thread Chuck Guzis via cctalk
On 09/06/2017 06:50 PM, Jon Elson wrote: > On 09/06/2017 12:11 PM, Chuck Guzis via cctalk wrote: >> Will do--I've mentioned in another message that I'm preparing a test >> tape using the drive, so I should get some inkling of timing and >> adjustments pretty quickly. --Chuck > While that is good,

Re: HP 7970B Capstan?

2017-09-06 Thread Chuck Guzis via cctalk
On 09/06/2017 06:50 PM, Jon Elson wrote: > On 09/06/2017 12:11 PM, Chuck Guzis via cctalk wrote: >> Will do--I've mentioned in another message that I'm preparing a test >> tape using the drive, so I should get some inkling of timing and >> adjustments pretty quickly. --Chuck > While that is good,

Re: HP 7970B Capstan?

2017-09-06 Thread Jon Elson via cctalk
On 09/06/2017 12:11 PM, Chuck Guzis via cctalk wrote: Will do--I've mentioned in another message that I'm preparing a test tape using the drive, so I should get some inkling of timing and adjustments pretty quickly. --Chuck While that is good, an all-ones test tape made on ANOTHER drive that

Re: HP 7970B Capstan?

2017-09-06 Thread Chuck Guzis via cctalk
On 09/06/2017 09:41 AM, Jon Elson via cctalk wrote: > On 09/06/2017 11:03 AM, Al Kossow via cctalk wrote: >> >> On 9/5/17 11:09 PM, Chuck Guzis via cctalk wrote: >> >>> The read results have improved considerably. >> tension arm servo acting reasonably? >> >> what style arm sensor does your drive

Re: HP 7970B Capstan?

2017-09-06 Thread Jon Elson via cctalk
On 09/06/2017 11:03 AM, Al Kossow via cctalk wrote: On 9/5/17 11:09 PM, Chuck Guzis via cctalk wrote: The read results have improved considerably. tension arm servo acting reasonably? what style arm sensor does your drive have? OK, so one of the first checks is to put a scope on the

Re: HP 7970B Capstan?

2017-09-06 Thread Al Kossow via cctalk
On 9/5/17 11:09 PM, Chuck Guzis via cctalk wrote: > The read results have improved considerably. tension arm servo acting reasonably? what style arm sensor does your drive have?

RE: HP 7970B Capstan?

2017-09-06 Thread Rik Bos via cctalk
> -Oorspronkelijk bericht- > Van: cctalk [mailto:cctalk-boun...@classiccmp.org] Namens Chuck Guzis via > cctalk > Verzonden: woensdag 6 september 2017 8:09 > Aan: CCtalk <cctalk@classiccmp.org> > Onderwerp: Re: HP 7970B Capstan? > > On 09/05/2017 10:47 PM,

Re: HP 7970B Capstan?

2017-09-06 Thread Chuck Guzis via cctalk
On 09/05/2017 10:47 PM, David Collins wrote: > From my old HP CE days you could always get black off the capstan if > you used alcohol or similar (never recommended). The key thing is it > shouldn't be sticky/gooey. I noticed the issue by starting a read from load point and observing that the bit

Re: HP 7970B Capstan?

2017-09-05 Thread David Collins via cctalk
-Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis > via cctalk > Sent: Monday, September 04, 2017 9:17 PM > To: CCtalk > Subject: HP 7970B Capstan? > > I've got an HP 7970 tape drive here that's a little dicey on its re

RE: HP 7970B Capstan?

2017-09-05 Thread CuriousMarc via cctalk
PM To: CCtalk Subject: HP 7970B Capstan? I've got an HP 7970 tape drive here that's a little dicey on its reading (haven't tried writing yet). One thing that I noticed today was that the surface of the capstan is a bit powdery--wipe it with an alcohol swab and you get a lot of black schmutz

Re: HP 7970B Capstan?

2017-09-05 Thread Chuck Guzis via cctalk
On 09/05/2017 10:55 AM, Jon Elson wrote: > Some spring-arm drives had really bad problems with tape slipping. I > know some Pertecs had circular grooves in the capstan to prevent an air > bearing effect. On one of our spring-arm drives, I cut thumbs out of > latex gloves and stretched them over

Re: HP 7970B Capstan?

2017-09-05 Thread Jon Elson via cctalk
On 09/04/2017 11:16 PM, Chuck Guzis via cctalk wrote: I've got an HP 7970 tape drive here that's a little dicey on its reading (haven't tried writing yet). One thing that I noticed today was that the surface of the capstan is a bit powdery--wipe it with an alcohol swab and you get a lot of

Re: HP 7970B Capstan?

2017-09-04 Thread Chuck Guzis via cctalk
On 09/04/2017 09:41 PM, Mike Loewen via cctalk wrote: > On Mon, 4 Sep 2017, Chuck Guzis via cctalk wrote: > > > >The rubber on my 7970E capstan is not tacky, but fairly firm. I've > used Techspray Rubber Roller Rejuvenator successfully on keypunch > rollers to make them a bit "grippier" -

Re: HP 7970B Capstan?

2017-09-04 Thread Mike Loewen via cctalk
On Mon, 4 Sep 2017, Chuck Guzis via cctalk wrote: I've got an HP 7970 tape drive here that's a little dicey on its reading (haven't tried writing yet). One thing that I noticed today was that the surface of the capstan is a bit powdery--wipe it with an alcohol swab and you get a lot of black

HP 7970B Capstan?

2017-09-04 Thread Chuck Guzis via cctalk
I've got an HP 7970 tape drive here that's a little dicey on its reading (haven't tried writing yet). One thing that I noticed today was that the surface of the capstan is a bit powdery--wipe it with an alcohol swab and you get a lot of black schmutz. It wasn't very soft and it occurred to me