The distance is about 4 inches or less I believe. I can measure it.

Glen, I bought a 16500C on ebay but it was not packed well and the front panel metal frame was broken as well as one of the tabs that holds the pems nuts on the front panel. It is also missing, i think, one of the 4 position black IR "directors" that mount on top of the photo transistors on the curved circuit boards at the bottom of the display. If I have to I can harvest them from my 16500b but I prefer not to ruin a perfectly good unit to repair another. The part numbers that I can find are: MP1 16500-40201 Front Panel MP22 5021-5807 Frame Front I cannot find a parts list for the IR Detector circuit board. I am also still looking for the 80 pin high density cable to connect the 16500B main circuit board to the lan interface board. The part # for the additional cable that I am looking for is 16500-61614. Do you know where I can find either a dead 16500C I can harvest the parts from or know where I can get the parts? Thank you, Mike bitwiz(a)12bitsbest.com On 9/20/2026 12:44 AM, Glen Slick via cctalk wrote: tab reverse

Hi all, I‘m quite interested in your experience with 16500 Maimframes. Mine is not very good, since I tried some of them. Each one died with a defective PSU Board, some died very spectacular. Since the psu board is very complex as well as there seems to be no schematics available I gave up on these systems. I‘d like to give them another try. Best Andreas > Am 26.09.2026 um 21:37 schrieb Adrian Godwin via cctalk <cctalk(a)classiccmp.org>rg>: > > I have some 16500A frames which uses a similar panel. The rotary encoder > and contrast/brightness controls are a little different but the IR section > may be the same. > >> On Sat, Sep 26, 2026 at 6:06 PM Mike Katz via cctalk <cctalk(a)classiccmp.org> >> wrote: >> >> Glen, >> >> I bought a 16500C on ebay but it was not packed well and the front panel >> metal frame was broken as well as one of the tabs that holds the pems >> nuts on the front panel. It is also missing, i think, one of the 4 >> position black IR "directors" that mount on top of the photo transistors >> on the curved circuit boards at the bottom of the display. >> >> If I have to I can harvest them from my 16500b but I prefer not to ruin >> a perfectly good unit to repair another. >> >> The part numbers that I can find are: >> >> MP1 16500-40201 Front Panel >> MP22 5021-5807 Frame Front >> >> I cannot find a parts list for the IR Detector circuit board. >> >> I am also still looking for the 80 pin high density cable to connect the >> 16500B main circuit board to the lan interface board. The part # for the >> additional cable that I am looking for is 16500-61614. >> >> Do you know where I can find either a dead 16500C I can harvest the >> parts from or know where I can get the parts? >> >> Thank you, >> >> Mike >> bitwiz(a)12bitsbest.com >> >> >> >>> On 9/20/2026 12:44 AM, Glen Slick via cctalk wrote: >>> On Sat, Sep 19, 2026, 9:33 PM Mike Katz via cctalk<cctalk(a)classiccmp.org >>> >>> wrote: >>> >>>> The distance is about 4 inches or less I believe. I can measure it. >>>> >>> The 80 conductor 16550A cable might be too short. Also, it might be keyed >>> the wrong way even if it was long enough. The 16550A cable polarization >> tab >>> is keyed pin 1 to pin 1, while the 16500B / 16500L/H cable might be >> reverse >>> keyed between the two ends. I'd have to pull the lid off of a 16500B to >>> check. >>>

On Sat, Sep 19, 2026, 8:47 PM Mike Katz via cctalk <cctalk(a)classiccmp.org> wrote: I wonder if the 80 conductor cables on the 16550A modules use the same connectors, and if so, if those cables are long enough to connect between a 16500B CPU board and a 16500L or 16500H board. I'll have to see if I can find the time to answer that question. If the answers are yes, it might be easier to acquire an 80 conductor cable from a 16550A module than a 16500L / 16500H cable. I have some 16550A modules that I don't have much real reason to ever use instead of 16555A or better modules.

On Sat, Sep 19, 2026, 10:03 PM Mike Katz via cctalk <cctalk(a)classiccmp.org> wrote: The 16554/5/6/7 modules have a 20 conductor cable plugged between two connectors on a single module configuration. On a multiple module configuration one end of the cable is unplugged from one of the connectors on each of the expander boards and plugged into a different connector on the master board. Also, an additional pair of cables is needed to connect between a pair of connectors on each board of a multiple board set. HP part number 16555-68701 or 16555-68705 is a set of pairs of cables for different numbers of boards in the set. 16555 are limited to 3 board sets, 16556/7 up to 5 board sets. For example item 263655364718 or 355859408593 on eBay.

Glen, Thank you, I just ordered a set of the 1655X cables, the seller is about 3 miles from me.  So no shipping involved.  I also asked him about the 80 pin high density cable. thank you for all of your help. Now I need to get two 16577D boards, one 16534A board, one 16534A and one 16522A.  And then if I can get lucky a a 16505 to help me design a debug board for my PDP-8/E computer from the 70's. I also have a 16500C coming from ebay, I plan on putting all of the good cards in that and then selling the 16500b with the LAN and Memory upgrade. Thank you for all of your help,                    Mike. On 9/20/2026 12:20 AM, Glen Slick via cctalk wrote: