Re: "non-polar" capacitor?

On 07/30/2016 10:24 PM, Jim Brain wrote: > Since I acquired a Coco Orchestra 90 unit awhile back, and I am > trying to find the source of some humming in my system when the Orch > 90 unit is operational, I looked at the schematic: > > >

Re: "non-polar" capacitor?

Jim, These are non-polarized (or bi-polar) electrolytics. An example is the following digikey part number: 493-12697-3-ND You can always whip one up out of your junk box - just put 2 normal (polarized) electrolytic in series with the polarities alternating (for example, connect the two

"non-polar" capacitor?

Since I acquired a Coco Orchestra 90 unit awhile back, and I am trying to find the source of some humming in my system when the Orch 90 unit is operational, I looked at the schematic:

Re: formatting and checking floppy disks for bad sectors

On Sun, 31 Jul 2016, Maciej W. Rozycki wrote: From my experience with floppy formats and reasonably fast computers (i.e. where CPU processing latency doesn't really matter) the best results are obtained with no interleaving, no sector staggering on head switching, and single-sector staggering on

Re: formatting and checking floppy disks for bad sectors

When I have to go through piles of floppies (and I do this more often than I care to) I make a master iamge of a good floppy and then copy with format+verify, aborting on the first error. The reason is quite simple--floppies with bad spots never get better, they only get worse. So you might as

Re: formatting and checking floppy disks for bad sectors

On Sat, 30 Jul 2016, Fred Cisin wrote: > > I highly recommend it if you're still into the floppy business > > and don't use Linux. The plain `format' command supplied with DOS gives > > you little control really and produces poor performance floppies. > > My PCs (original 5150 and IBM 5160

DEQNA and VMS 5, was Re: MicroVax II

On 07/29/2016 19:30, Jerry Weiss wrote: > > Note that DEQNA will not work (at all) on either version. > You’ll need a DELQA. On 07/30/2016 08:50, Paul Koning wrote: > > Yes, VMS stopped supporting the QNA at some point because, even > after 12 ECOs, it could not be made to work properly. If I

Re: Question re Teac MT-2ST encoder roller tire

On 7/29/2016 2:29 PM, Chuck Guzis wrote: On 07/29/2016 12:07 PM, j...@cimmeri.com wrote: Recently acquired a Teac MT-2ST SCSI cassette tape drive and am attempting to recondition it. Although it does have direct drive motors on both reels (no rubber bands), the design is still plagued by

Re: formatting and checking floppy disks for bad sectors

On Sun, 31 Jul 2016, Maciej W. Rozycki wrote: There used to be a `fdformat' utility available providing fancy stuff for DOS users like sector physical and logical shifting, interleaving, unusual geometries, etc. Be aware that FDFORMAT is ALSO the name of Linux low-level formatter, AND a

Re: the value of old test and repair equipment

In fact, the value of old test gear varies tremendously.. Vacuum tube testers of certain makes & models are near the top of the food chain, with clean, working examples pulling $1500+ (USD) on a very regular basis. There's also a strong following for much 'classic' audio analysis gear (HD

Re: formatting and checking floppy disks for bad sectors

On Sat, 30 Jul 2016, Fred Cisin wrote: > > I have a heap of floppy disks on hand. Most with old junk on them. Some are > > going bad, and have bad spots in the middle of the disk. Is there a good > > utility for either windows or dos that can format a floppy and mark the bad > > parts of the

Re: formatting and checking floppy disks for bad sectors

On Sat, 30 Jul 2016, devin davison wrote: I have a heap of floppy disks on hand. Most with old junk on them. Some are going bad, and have bad spots in the middle of the disk. Is there a good utility for either windows or dos that can format a floppy and mark the bad parts of the floppy to not be

formatting and checking floppy disks for bad sectors

I have a heap of floppy disks on hand. Most with old junk on them. Some are going bad, and have bad spots in the middle of the disk. Is there a good utility for either windows or dos that can format a floppy and mark the bad parts of the floppy to not be used? If anything, such a utility can let

Re: KT-24 and/or -11/24 backplane info

>> I guess it will require getting ahold of a backplane, and seeing what >> I can find out with an ohm-meter. > It looks like I'll still have to do this at some point, to confirm my > theories about how the two busses are wired on the backplane > (separation of UB and EUB

Re: Concurrent Computer Corporation

Is there a part number on the nvram? The chips Sun used with the enbedded battery were a standard part available from Mouser. Or is there a visible battery on the board anywhere?

Re: VCF West tickets

Pre-order ticket sales for VCF West end tomorrow at midnight ET. More available at the gate. https://t.co/kHKFAAn0TB $20 one day $30 both days But, what is the price to buy a ticket at the door? Same price. Pre-ordering saves time.

Re: VCF West tickets

On Sat, 30 Jul 2016, Evan Koblentz wrote: Pre-order ticket sales for VCF West end tomorrow at midnight ET. More available at the gate. https://t.co/kHKFAAn0TB $20 one day $30 both days But, what is the price to buy a ticket at the door?

VCF West tickets

Pre-order ticket sales for VCF West end tomorrow at midnight ET. More available at the gate. https://t.co/kHKFAAn0TB

Re: more vintage computer stuff

One other addendum to my last point- oftentimes they mutilate the vintage devices too- They'll dremel out a place to put a USB port on a vintage keyboard, or worse- harvest keyswitches out of them. I once had a keyboard collector offer to buy a working GRiD Compass 1129 off of me so they could

Re: more vintage computer stuff

Cindy wrote: > I also participate in at least one of the "dreaded" keyboard forums. > Why are they so dreaded to you guys? Because they do things like ask the seller of the totally complete, obscenely rare Symbolics 3620 on eBay in Finland if they can pay full price but leave the system behind

Re: Concurrent Computer Corporation

On Sat, Jul 30, 2016 at 01:58:49PM -0400, alexmcwhir...@triadic.us wrote: > I know nothing about this machine in particular, but i know a decent amount > about other unix machines of the era. Chances are that the copy of RTU on > that box is licensed to the serial / id number programmed in nvram.

Re: Concurrent Computer Corporation

Have u tried replacing said dead battery would start there On Jul 30, 2016 12:51 PM, "Pontus Pihlgren" wrote: > Hi > > I'm trying to revive and old unix machine. A Concurrent Computer > Corporation series 8000. This seems to be a later version of Masscomp > MC5600/MC5700

Concurrent Computer Corporation

Hi I'm trying to revive and old unix machine. A Concurrent Computer Corporation series 8000. This seems to be a later version of Masscomp MC5600/MC5700 which has a manual in bitsavers. The system runs RTU (which I assumes means Real Time Unix). My machine is in great condition and both SCSI

Re: MicroVax II

On Sat, 30 Jul 2016, Greg Stark wrote: > The hardest part was getting mopd on Linux to serve up the NetBSD boot > loader properly. The mopd for Linux didn't support ELF images and the > NetBSD boot loader isn't in mopd format in more recent versions of > NetBSD like it was in older versions. Now

Netbooting NetBSD/vax - was Re: MicroVax II

On 2016-07-30 12:09 PM, Greg Stark wrote: On Sat, Jul 30, 2016 at 2:38 AM, Mouse wrote: What OS's can I use with this hardware? NetBSD? Yes. Recent (and some not-so-recent) versions are broken, in that they can't self-host; as far as I know nobody knows exactly

Re: MicroVax II

On Sat, Jul 30, 2016 at 5:09 PM, Greg Stark wrote: > headaches. Even the GCC in 6.1.5 is a bit buggy. I had to recompile > awk with -O0 or else various s/$/ configure scripts failed./ -- greg

Re: MicroVax II

On Sat, Jul 30, 2016 at 2:38 AM, Mouse wrote: >> What OS's can I use with this hardware? NetBSD? > > Yes. Recent (and some not-so-recent) versions are broken, in that they > can't self-host; as far as I know nobody knows exactly what's wrong. > My impression (as

Re: MicroVax II

On Jul 30, 2016, at 10:26 AM, Douglas Taylor wrote: > > On 7/29/2016 10:30 PM, Jerry Weiss wrote: >> On Jul 29, 2016, at 8:30 PM, Zane Healy wrote: >>> On Jul 29, 2016, at 6:08 PM, Douglas Taylor wrote: I

Re: MicroVax II

> On Jul 30, 2016, at 8:52 AM, Douglas Taylor wrote: > > I agree, I remember using a MicroVax II in the BA123 box back in the mid > 1980's and wanted to have one and now I do. > > The only thing I forgot was just how heavy the damn thing is! > > I just looked and here

Re: MicroVax II

On 7/30/2016 11:50 AM, Paul Koning wrote: On Jul 29, 2016, at 10:30 PM, Jerry Weiss wrote: ... I have booted both V7.3 and V5.5-2 off a 4GB SD with SCSI2SD V4.6 on a MicroVax II with 16 Mb. Note that DEQNA will not work (at all) on either version. You’ll need a DELQA.

Re: MicroVax II

> On Jul 30, 2016, at 8:19 AM, Douglas Taylor wrote: > > I have a couple of Viking (TD Systems) scsi controllers which is what I am > thinking of using. I have some S-Box SCSI controllers then may come in handy. > > I like the idea of VMS 5.5 just to restore the

Re: MicroVax II

On 7/29/2016 10:55 PM, Glen Slick wrote: On Fri, Jul 29, 2016 at 6:08 PM, Douglas Taylor wrote: I just got a MicroVax II in the BA123 world box chassis. I has a TK50, RX50, RXDQ2, but no DEQNA. I'd like to get it running an OS. The DU disks don't work, but I have a

Re: MicroVax II

> On Jul 29, 2016, at 10:30 PM, Jerry Weiss wrote: > > ... > I have booted both V7.3 and V5.5-2 off a 4GB SD with SCSI2SD V4.6 on a > MicroVax II with 16 Mb. Note that DEQNA will not work (at all) on either > version. You’ll need a DELQA. Yes, VMS stopped supporting the

Re: MicroVax II

On 7/29/2016 10:30 PM, Jerry Weiss wrote: On Jul 29, 2016, at 8:30 PM, Zane Healy wrote: On Jul 29, 2016, at 6:08 PM, Douglas Taylor wrote: I just got a MicroVax II in the BA123 world box chassis. I has a TK50, RX50, RXDQ2, but no DEQNA. I'd

Re: MicroVax II

On 7/29/2016 9:30 PM, Zane Healy wrote: On Jul 29, 2016, at 6:08 PM, Douglas Taylor wrote: I just got a MicroVax II in the BA123 world box chassis. I has a TK50, RX50, RXDQ2, but no DEQNA. I'd like to get it running an OS. The DU disks don't work, but I have a

help identify Unisys memory board

Hi A rather large Unisys memory board came up for sale locally. The seller doesn't know much about it and I'm curious which machine it comes from. Here are some picture, fairly low resolution I'm afraid: http://www.pdp8.se/slask/unisys_mem/ Do you know what it might be? Thanks, Pontus.