Dead-bug soldering is an acceptable method to patch a production circuit board per IPC-7721. Awww, even looking at it is painful, there must be a lot of industrial horror stories behind these photos...

...and deliberately tombstoning an SMD resistor to install a mod wire to a production board is acceptable, too. From now on, whenever I do this I'll claim the board is hacked using the recommended industry standard technique.

...and the classic hack: stacking DIP chips on top of each other, lifting or cutting QFP pins for mod wires, are all accepted by IPC-7721 as legitimate methods for patching a production board. Interestingly, IPC-A-610 even allows stacked SMD resistors and capacitors by design, not limited to a modification.

Mod wires do have to follow some rules: secured by epoxy glue, not perpendicular to the pin, not crossing a component, and only a single wire should be used at a single pin. Also, zero-ohm resistors are acceptable pin bridges.

@theruran Stacking DIP chips on top of each won't work for most systems. But it's a classic way to do a RAM/ROM mod in a 8/16-bit computer because these chips are special - all data and address pins have the same pinout and are connected together on the same tri-state bus to carry the same signals, so you can stack one on another. The only different signal is the Chip Select pin, you cut that pin and solder a jumper wire to the decoder logic you added so only one chip is selected at a time. tag

@niconiconi you can get pre-stacked capacitors too, if you look for really high capacitance C0G ceramics

@niconiconi may I add, I'm also guilty of mounting smd resistors on their side. by design. pcb estate was tiGht :////

@niconiconi ahhh gosh. "oops, the resistor went upright when soldering, let's add a solder wire"

@JennyFluff @niconiconi Accidentally trying to solder with a length of hair got me.

@JennyFluff It takes 10 second to fix a tombstoning resistor. The only reasonable use of this technique is when one resistor pad is connected to the wrong place due to a bug in the design and you need to patch that up (because you already made hundreds of boards). i've seen an astounding number of bodges in avionics hardware i've looked at

@niconiconi I haven't seen this in this thread so I think this needs to be posted.
You can go even further with some bodges and claim they are according to NASA standards.
See, section 3.02 and 3.03

@ripper Thanks for posting. I know this NASA manual, but I didn't know it has an updated HTML version.

@niconiconi Yeah, I didn't know that too. I was searching for the PDF to link it, but found this instead.

@niconiconi @ekaitz_zarraga We used to call those barnicles. Once the effort required got past a set threshold we’d re-spin the boards. When you’ve got 10,000 components on a 12 layer stack that’s a lot of barnicles you’ll live with though.
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