PCB Failures

Mk3 (GHD3, 3.1B, SS2 etc)

Mk3 PCBs virtually never fail. The only real issue we've come across is dodgy switches which can be fixed with a bit of switch cleaner.

Mk4 (GHD 4.0B, 4.1B, 4.2B, SS4.0 etc) & Mk5 (GHD 5.0, MS5, SS5 and SC5)

Mk4 & Mk5 PCBs normally fail with R8 or R11 resistor failures. If your irons are dead, then it could well be one of these resistors is open circuit. See the R8/R11 page for more information.

The other resistors on the PCB are very high resistance (>1Meg Ohm) so you may not be able to measure them in circuit. This does not mean they are faulty - the only resistors that ever fail are R8 and R11.

If your board does not have an R8/R11 resistor problem and you are sure it's the board (i.e. heaters measure correctly, thermal fuse and cable are ok etc) then here are some problems that have been reported:

 

Another infrequent PCB caused fault can be low operating temperature.

Check R1, it must be measured out of circuit and should be 1 Meg ohm. Replace it if reads any higher than 1 Meg Ohm.

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