Currently fitting a chip to my classic, and having a few issues regarding the 28 pin "2nd slot". I have found on my board that pins 27 & 28 are bridged, and i was wondering if anyone knew their functions. Me and my mate can only think they`re 2 x power supply....... or aren`t they supposed to be bridged.
Any one with any ideas??

 

what chip is it mate, what are they bridged with the PCB or solder? they shouldn't be bridged on your ecu don't fit the chip as it is or it could should it out

 

Got from major_sarcasm, if thats the case i`ll get the slot de-soldered and go again. Doesn`t seem to be excess solder though , my mates a good electrical engineer and does a good job, but you never know, the pcb fits snug so you cant actually see properly.

Thanks

 

Pin 28 is VCC, and should be at +5V

Pin 27 is /PGM, the EPROM programming pin. This should also be pulled up to +5V (voltage levels of 0V to +12.5V are used to program the EPROM, but in situ it should be held at 5V)

I haven't checked a board, but a short between pin 27 and 28 seems likely to be correct to me. Hold off and I'll check an ECU for you.

 

OK, managed to double check a known good U8 board.

Pins 27 and 28 do indeed seem to be shorted on the ECU board, so it should be okay.

Of course, you're on your own if all this info is wrong

 

Thanks Chief, thats what we figured as the solder job he did is pretty neat. Just ruling out possibilities for this chip not to operate.