Engineering porn - Page 1
Forum section: electronics / general

author: Eliminateur
author_rank: Regular Contributor
timestamp: March 19, 2011, 12:36:31 am
content: YEAHHH because we all love those shiny, beautiful and exotic.... PCBs full of circuits!since i have access to all sorts of equipment and i had the cammera at hand, here's my engineering porn for the day:old(broken) DEC Alpha 1KW PSUs, i think it's 5V @1KW, the two boards in the photo are stacked, one of them(the one i took out all the big juicy caps) is the rectifier + PFC(yes, it has ACTIVE PFC, in a 1990 PSU).the other one has all the electronics, look at that fat big Motorola microcontroller for the beast, it's filled with current transformers as well for monitoring and a ton of passives.Look at the soldering!, look at that HUGE towering output COIL, yes, that white towring piece of flat metal is a inductor! look at the output transformer, it uses sheet metal!, insane!, look at the output connectors!we could never repair themn, some sub-psu hybrid aux module inside fried, the picture is on the shelf you can see the sheer size compared to UPS 12v gel cels.oh and look at that input protection with dual-pole thermomagnetic breakers inside!ah yes, the boards are Astec branded, dated 1990/1991, don't know if they still exist now...http://img809.imageshack.us/g/dsc00961uj.jpg/aaaand the rest, Scientific Atlanta KU band sat transmitter, 1995~ vintage, i opened a couple for pure curiosity(i have like 5 of those, brand new in box, with the warranty seals intact from when we deployed large dishes).Both are same model, 6605 but one made in italy(the slimmer -newer- one with huge heatsink) and the other in Japan(filled with components, bigger but overall same size if we include the heatsinks).i don't know what components are the PCB made of, one is white, the other brown-black, both are single sided with very weird tracks, everything seems to be very esoteric-rf-engineered!, in fact, the RF path is not electrically coupled, it has like "induction" paths throughout the circuit and finally it goes to the output pin on the other side in some kind of serpentine resonance chamber, the fine tuning is made with those 4 screws!, it's plainly amazing, all solid cast aluminum water-tight.the DC power comes from the RF connector as well and some LM350+dc/dc converters, if anyone can shed more light it would be awesome!. From what i could infer from the newer one, it's controlled by a MC68000 micro that directly controls a 16dB digital attenuator chip, the RF pass through it to the esoteric brown part....and the final photo with feedhorn and LNB attached, everything is solid cast metal!http://img845.imageshack.us/g/dsc00947.jpg/so, post your eng porn in as higher res as you can and with all the data you can, maybe someone else will be able to shed more light on them!

author: tesla500
author_rank: Regular Contributor
timestamp: March 19, 2011, 07:19:40 am
content: Ohhhh, I love electronics porn! I'll have to make some.What PFC controller did they use in that DEC power supply? Or was it discrete components?

author: Eliminateur
author_rank: Regular Contributor
timestamp: March 19, 2011, 04:50:31 pm
content: you can barely see it in the picture, it's on the "power" board(the one with the big desoldered caps and the microcontroller), you can see a vertical daughterboard, that's the PFC controller, it's already integrated!, the level of engineering and brute force in this unit amazes me(and monitoring, the edge connector had all sorts of diagnostic signals).I haven't paid exact attention to the PFC chip, i'll take more detailed pictures of that part other dayAfter all, it's 200Amps @5V!

author: chscholz
author_rank: Regular Contributor
timestamp: March 19, 2011, 08:22:09 pm
content: 45 GHz scope, 20x20GHz channel scope, would that qualify?

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 19, 2011, 09:23:42 pm
content: yerr right. engineering porn. this is what i got on my screen. better than google ads.

author: Franki
author_rank: Regular Contributor
timestamp: March 19, 2011, 11:34:04 pm
content: ha ha, just found this thread.to me, this is porn

author: Eliminateur
author_rank: Regular Contributor
timestamp: March 20, 2011, 04:39:43 pm
content: Quote from: chscholz on March 19, 2011, 08:22:09 pmif you have high res closeup photos of it's insides or at least the front/back then yeah