Wednesday, June 19, 2019

2015 iMac Disaster

Well gang, it wasn't long before the repair/upgrade of my 27" 2015 iMac came to grief. I got up, walked in the room and there before me was a computer with its display lying on the edge of beloved Herman Miller Ferrari-colored computer chair. I was so horrified that I didn't even think to take a picture of that appalling tableau. No, no one else will ever have the sadly-missed golden opportunity to co-experience such an exquisite non-rush.

I stood there in a daze for some time. Reality itself was beyond my capacity to entertain. πŸ˜‘

I finally came out of my stupor. As I gingerly lifted the display up and turned it over I beheld cracks aplenty:

Full screen (click to enlarge)

Right end

Needless to say the video and back-light cables were no longer in their sockets on the logic board. Having worked on aluminum iMacs numerous times I immediately assumed the worst. That is, all surface-mount connectors ripped clean off the PC board. Amazingly, the backlight connector had no damage at all. The embedded DisplayPort (eDP) connector only had its ends bent.

Backlight connector
eDP connector
There was virtually no adhesive residue on the back of the display except along the bottom which was still quite tacky and one small spot about an inch wide elsewhere. The frame was also tacky but not as much as it should have been.

We wiped everything down with IPA before we put the new adhesive strips on. Perhaps we rubbed the strips too hard while we were putting them on the case. I'm sure this is a pressure-sensitive adhesive so that may have made it start to cure before we got the display on. OTOH, we may not have rubbed things together as tightly as we should have after the display was on. At this point I don't know what to think.

Better pictures to come when we take it apart again to replace the display. 😷

Thank "Bob" it didn't reach the floor. At least it's still working.


Thursday, June 13, 2019

Eldorado 325A Frequency Counter

My latest acquisition from eBay:

From the seller's photo (heavily retouched by me)
Works perfectly down to 1Hz. I haven't tested the high end yet. I had a shoot all set up but as usual a disaster cropped elsewhere. I'll update this post with more pictures later if I have the chance.

$67. I was the only bidder.

The next day a model 224 with only four settings went for $65. πŸ™„

Friday, June 7, 2019

Systron Donner 6052 Frequency Counter

This is a work in progress...

Here is an HDR image:
Click to enlarge
The least-significant digit is working properly. The long exposure time captured it bouncing between zero and one. Note how the HDR processing has exaggerated every speck of rust and dirt around the knob. Live and in person it looks less grubby.

I just realized that this unit has nine decades, not eight. Excellent for a portable, desktop frequency counter.