Oh Joy.. reverse engineering

Started by Rx7man, April 29, 2018, 04:34:16 PM

Rx7man

I have a problem with my welder.. suspecting the high power board.. AC generator works, no weld output though, mechanics are fine,.. and of course schematics are "proprietary" and unavailable.. Board has about $200 worth of components, certainly could be designed as a 2 layer with a few vias (no vias, thankfully, that would make tracing harder)

3 layer board, 55 resistors, 25 capacitors, 40 diodes, few rectifiers, half dozen high power transistors, 4 optocouplers, couple op-amps, and about 30 connectors.. I'm just lucky it's a very translucent board and I don't have to probe everything, I can see the center plane through it, and mostly just fine traces there.

Once I get it drawn out I can start troubleshooting and see if it's the control circuitry or the power section that's not working
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

hakcenter

omg is that 45 degree angles in the schematic phase ? noooooooooooooooooooooooo
TS2009 Deḇarim 8:2
"And you shall remember that יהוה your Elohim led you all the way these forty years in the wilderness, to humble you, prove you, to know what is in your heart, whether you guard His commands or not.

Rx7man

yes, yes they are.. I'm trying to make the schematic approximately like the board, or I'll never see it through.. maybe when I'm done I'll make a second copy where I organize everything nicely... and don't have wires going through devices.  As you see, for now, with some of the devices they're just black boxes that look like the physical device.. later I'll fix that too.. maybe.
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

Rx7man

Oh, yeah, I was told it's a 3 layer board.. they're wrong, it's 4 layer..
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

Rx7man

I'm grinding away at it.. nearly done.. Had to desolder 2 of the control relays and an 11 pin transformer..  Really hard to trace the circuits on the center layers if there are devices with continuity.. (hence the need to desolder) they also use a VERY high temp solder, so it took a lot of solder wick, had the iron cranked right up to 500F, and to top it all off, the devices/board have conformal coating on them which makes them hard to work, and it glues things down.. Well, I see the finish line at least!
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

Rx7man

OK.. Does this look better?  that was a dozen hours work.
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

hakcenter

TS2009 Deḇarim 8:2
"And you shall remember that יהוה your Elohim led you all the way these forty years in the wilderness, to humble you, prove you, to know what is in your heart, whether you guard His commands or not.

Rx7man

'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles

hakcenter

TS2009 Deḇarim 8:2
"And you shall remember that יהוה your Elohim led you all the way these forty years in the wilderness, to humble you, prove you, to know what is in your heart, whether you guard His commands or not.

Rx7man

I was debating whether I should lay it out with labels for some of the common stuff or actually wire it... couple of them were a pain.. no way to make them not cross all the way across the board
'94 dually,  67/67 HE351VE, NV5600, ~600hp
'93 ECLB 47RH, new toy truck, H pump project, 1000hp goal, 300K miles
93 XCLB auto, bone stock, 350K miles
93 XCLB 5spd, bone stock, 100K miles