DEC PDP-8 Paper Tapes

This page Last updated May 11 2023. My other DEC stuff is cataloged on the linked Web page. To email me or to order, see see my ordering Web page for my email addresses.

I acquired this set of DEC produced PDP-8 diagnostic paper tapes in May 2023. The photo on the right, shows their purchased condition. I proceeded to clean and restore the vinyl cover, the plastic tray and one of the bent paper tapes. The photo on the left, is the final cleaned results. Here's the list of paper tapes:

Maindec-08-dhrka-e-pb 06/06/77 RK8E diskless control test
Maindec-08-dhrka-d-pb 04/05/77 RK8E diskless control test
Maindec-08-dhrka-d-pb 03/25/77 RK8E diskless control test

Maindec-08-dhrkb-g-pb 03/11/77 RK8E Drive control test
Maindec-08-dhrkb-g-pb 04/05/77 RK8E Drive control test
Maindec-08-dhrkb-g-pb 06/06/77 RK8E Drive control test

Maindec-08-dhrkc-g-pb 03/25/77 RK8E Data reliability test

Maindec-08-dhrkc-h-pb 06/06/77 RK8E/RK8L Data Reliability programt
Maindec-08-dhrkc-h-pb 05/02/77 RK8E/RK8L Data Reliability program

Maindec-08-dhrkd-c-pb 03/24/77 RK8E Disk Formattter program
Maindec-08-dhrkd-d-pb 05/02/77 RK8E/8L Disk Formattter program
Maindec-08-dhrkd-d-pb 08/04/77 RK8E/8L Disk Formattter program

As sold, there were about a dozen tapes, in a plastic tape holder, encased in a vinyl tranparent pouch. When received I saw the plastics needed a cleaning to remove mold.

On the pouch, I used paper towels with water and slight dish detergent to clean the mold. Then I wiped the vinyl pouch with a restorative product, "Nu-Vinyl", which is now out of production. I put the bag in the sun to dry and to warm the bag so the product could migrate into the vinyl. Nu-Vinyl and other vinyl restoratives (automotive upholestry products)2may include plasticizers to replace the plasticizers dissipated from age. Also sunlight is a good disinfective. However prolonged UV exposure breaks down plastics.

I wiped the plastic tray in a similar fashion. The plastic clear sheet over the tray is particularly brittle and selectively yellowed. The blue tray is intact but likely brittle.

One of the paper tapes was folded over on the first several sections. A warm iron served to flatten out the folds. I also used the iron, cooled but still slightly warm, to iron a fold on the flap of the vinyl pouch.

Copyright © 2023 Herb Johnson