4 Dec
2021
4 Dec
'21
2:12 p.m.
If u hunt around u can find similar switches in e-waste or even new. Then
make some baskets u can attach. Like they did or if u got patience u can
take those right apart and rebuild as the pins sit in a cardboard like
material the plastic switch slides on with metal inserts for making
contact. Need to get around finishing rebuilding mine.
Mine had been ripped off but it u can see how they are assemble here
https://www.flickr.com/photos/1ajs/16586222513/in/album-72157651577592077/
On Sat., Dec. 4, 2021, 3:46 p.m. Chris Zach via cctalk, <
cctalk at classiccmp.org> wrote:
I've decided it's time to fix my second
pdp8/L. First one is missing (I
think it's at the bottom of the closet) so I'll work on this one for
awhile.
First problem: Testing the lamps and switches. If the switches don't
work or the lamps are out it's not going to be easy to troubleshoot.
Currently I'm missing 5 of the plastic switches, and I have 2-3 switches
with a broken pivot.
Since I was going to need new plastic switch covers I fired up the 3d
printer, downloaded the STL file for making them (thank you for putting
that up!) and ran off a few for testing. It helps a lot to set the
bridge angle value to 60% or so, that allows a nice solid bridge for the
two "teeth" that engage the rocker switch. Also don't bother with PLA:
The plastic pivots are too weak and break pretty quickly. Use PETG,
which requires higher heat (240 instead of 200 at the head and 70
instead of 60 at the base) but it is more than strong enough for the
pivots to go in without issues.
Testing the switches I found that one of the data/address switches was
reading high ohmage (20) when closed in the down direction and two of
the data entry (spring loaded) switches were intermittent. Sprayed in a
bit of Deoxit, and they now switch cleanly and without bounce. That
would probably have driven me crazy if I tried to test with that.
Next step: Check out the power supply.....
C