Very interesting. The parts I replaced I inserted exactly as they came off. I took several pics of these to ensure that, as a newcomer to powerboards, I fitted them correctly . I will make the adjustments and order the partsShould have said that the correct 47R resistor for R6 will have Yellow, Purple, Black stripes. Again there may be an additional Gold stripe to show 5% tolerance.
are these what I need? 5 X 0.47 ohm 2W Metal Film Resistor 0.47R 2 WattShould have said that the correct 47R resistor for R6 will have Yellow, Purple, Black stripes. Again there may be an additional Gold stripe to show 5% tolerance.
I'll go on my ebay account. That's where I got them.O.47R is wrong, that is 100x too low resistance. You need 47R 3watt. If you go back to the link earlier in the thread that you used to order the 47K resistor you will find that they do 47R 3W as well. I'm on my phone in the sunshine and can't see to scroll back that far!
All sorted. Enjoy your hols. Shall I drop a post when the board is back on with the new resistor?O.47R is wrong, that is 100x too low resistance. You need 47R 3watt. If you go back to the link earlier in the thread that you used to order the 47K resistor you will find that they do 47R 3W as well. I'm on my phone in the sunshine and can't see to scroll back that far!
Keith I can't find r6. Am I going nuts?OK thanks for the photos. I can see a number of problems that would explain why the 170V supply is not working:
1) TR2 appears to be fitted incorrectly. The tag on the side of the transistor should line up with the tag shown on the silk-screening on the pcb. The three legs on the transistor are grouped around one half of its base and these would then line up with the three holes in the board which are grouped around one side of the outline on the pcb.
2) I can't see the orientation of TR3 due to the heatsink on it, but the same may be true of that. It is essential that the leads of the transistors are in the correct holes or they will not work correctly and will generally be damaged as a result.
3) TR1 is incorrectly fitted. The metal side of the transistor should be laid flat towards the bottom of the heatsink and held tight to the heatsink by the brass pillar and bolt, with a small smear of the heatsink paste between the heatsink and the metal back of the transistor to improve the transfer of heat - that transistor gets very hot when it is working. The transistor should have the middle lead cut off and the other two go into the two holes on the board and are soldered in. You can see a faint outline on the heatsink of where the old transistor was. I will try to find a photo to show how it should look but I am away on holiday and can't easily take one.
4) R6 appears to be a 47K resistor (47,000 ohms) (Yellow, Purple, Orange) rather than the 47R (47 ohms) which needs to be fitted. The gold stripe at the end of the resistor just shows that the resistance value has a tolerance (accuracy) of 5%, which is fine.
The resistance of R6 being too high may have saved the transistors from damage, although if you have spares left I would use one for TR2 (and TR3 if it is wrongly aligned). The supplier you were linked to before for the replacement of R6 supplies both 47R and 47K resistors so you need to be careful to select the right one.
I'm sure once these problems are corrected you will have a working machine again. Obviously once you have replaced/corrected all of them you should disconnect CN5 and measure the voltage at Pin8 before we go any further. All of the above issues need to be corrected at the same time before trying things again or you may do further damage.
Yes i am doing it. But does the gold stripe go at the top?Trust me, R6 is the component you fitted before which has a yellow, purple and orange stripe, plus a gold stripe. You need to replace it with the 47R 3W resistor
Okay so here is what happened after I replaced the resistor. ....... ..... . All voltages are correct including a 168.5v read on pin 8 of CN5. And........ . .the game is 100% working as it should including the displays.Whichever way up looks prettiest - resistors are one of the few electronic components that cam be fitted either way round
That would be nice.It is an epic thread. I really love it. It epitomises everything that is brilliant about this forum and its members. Well done to both of you for your patience throughout. Special mention to Keith who stuck at it for no other reasons than just helping someone else. It would be lovely to have a pinball festival where you two could meet around a beer. Hopefully 2021 will bring one along.