douglas qbus extender board quality

[hush]

hey all, just a quick question about qbus extender boards- i'm likely going to need one to diagnose the failing VCB02 i have, but i've seen some concerns about the quality of their connectors. does anyone know if it is worth picking one of these up with connectors, or is there somewhere that i can source better quality ones?

thank you in advance!

 

[ftcnet]

compare with Todd Goodman's DEC Flip-Chip Extenders

 

[reinhardtjh]

I have no experience with the Douglas extenders. I bought the boards Todd Goodman is selling from Joerg Hoppe's design (linked to in ftcnet's post) and the connectors from him as well and soldered my own +5 quad and dual extender boards.

Link to previous discussion ==> https://forum.vcfed.org/index.php?threads/newly-acquired-11-23.1249474/post-1404823
Link to Order info for Todd Goodman ==> https://retrobrewcomputers.org/doku.php?id=boardinventory (scroll to nearly the bottom)
Link to Joerg Hoppe's site describing the boards ==> https://retrocmp.com/tools/dec-flip-chip-extenders

Price-wise the Todd Goodman version is a few buck less - For a Quad it's $75 (35 board+40 connectors) and Douglas is $90 but the connectors are pre-soldered. Three yeas ago (right around this time of year) Todd Goodman was fast - about a week to deliver. I don't know the delivery time for Douglas.

 

[hush]

ahhhh yep i'm familiar with todd, he still has pretty quick turnaround time, i bought my 68030 cromix boardset from him and it came pretty quick good to know, thank you both!

 

[Radix]

Some of the ones from the 1980s didn't use the DEC connectors - and they do not provide accurate location for the slightly narrower DEC board PCB contacts, so it is possible to insert the board to the left or right on the correct position, potentially causing disastrous shorts...

They can be used perfectly well, with care - and caution to make sure they locate in the backplane correctly as well.

It's also good to support the extended board on a suitable box or similar so you can get a scope on it more easily

Robin

 

[gwiley]

I bought a Douglas quad-height extender with connectors soldered almost 3 years ago. I think the overall quality is great... nice gold-plated connectors, fingers are gold, solder joints good. Pin alignment between the AB and CD sections is perfect. His assistant shipped out the extender the same day. Douglas Electronics and I are both in California so it arrived soon.

I wasn't aware of the extender from Todd Goodman at that time.

 

[shirsch]

Ditto on the Douglas extenders. Definitely built to last.

 

[hush]

that's good to know, i'm thinking that with 144 solder joints total for quad boards and only a $15 price difference per board i'm probably just gonna buy them from douglas... much less of a headache since i want at least two x)