Repair 16 - Bad transistor - verified as 8 lamps are out. Buzzed back to T28 on MPU3. T28 is different to the other transistors and is driven differently. (It has a remote transistor T37 and was an after thought mod because IC20 can only drive 7 outputs). Initially replaced with TIP127 transistor. Board ran for a few hours before the T28 burns up and fails again. R50 is hot. I replace T28 again and all is well, but 10 minutes in it burns up, resulting is thermal ‘runaway’ and the transistor is lost. I spoke to a few people on the Mecca... It turns out that TIP127 is not a strong enough transistor so I used a donor off a scrap board. All sorted. My fault, my mistake. I must used the correct part, I must use the correct part, I must used the correct par...