Board PCB discussion

[Tony]

Suggestions for improvements, mistakes, hints here please.

[Digital_Dan]

Resistor R1

unnamed.jpg (10.64 KiB) Viewed 26881 times

Is the R1 resistor on the case boards .47 or 47 ohm? I have a board with a dead resistor and am having trouble definitively figuring out what it's value is. The original resistor is reddish orange background with black, yellow, violet, silver and gold stripes. The trouble comes from deciding whether to start with the black or yellow stripe when figuring the value.

Thanks

[Tony]

It's 0.47R, 047/100 though the black band doesn't really add much information there. It's a fusible resistor designed to fail if there's a fault and must not be permanently replaced with an ordinary resistor though for faultfinding a temporary .47 - 1R resistor will be OK.

[Digital_Dan]

Ok, now I need at least one (or preferably 2 or 3) but here at the end of the food chain they're just not available. Is there an online source where I can buy less than a thousand or can I buy them from you?

[Tony]

They shouldn't be too hard to find, what suppliers do you have access to locally and I'll see if they have anything listed?. I know Mouser has them but the minimum order charge may be a problem.

[Digital_Dan]

Thanks Tony,

I think I finally managed to get some from Allied Electronics after I finally tracked down a good part number. It only took me an hour and a half of searching the internet... I had to buy 10 resistors, pay a $5.00 handling fee and $6.50 for postage for .17 cent resistors but at least I didn't have to buy 4-10,000 of them like those crafty Chinese folks wanted . Only thing around here selling electronics parts is Radio Shack and they didn't even have .47 ohm regular resistor much less a fusible. As I mentioned, Fairbanks, Alaska is at the end of the food chain and we kind of live on the internet for buying many things. The trouble with that is most people want to charge you exorbitant sums to ship things here because they think everything has to come FedEx or UPS second day or faster. Soooo, looks like I'm back in business once they arrive. I'll keep you posted.

Thanks again!

[Digital_Dan]

Resistors arrived yesterday. All four circuit boards working again although I note a couple of squares on one board the that don't seem to provide as much power as the others and the pieces only light weakly. What should I check on those squares?

[Tony]

Is it the same board that had problems with the 0.47R?. Check the 1n tuning caps are correct, replace one just to make sure. Are the coils running warmer than the rest that work OK?.

[elentar]

Ordered my kit in April 2017, and noticed a few changes from what's discussed here. These tips may help someone else getting started with this project:

• There is no ferrite link for the x64 single piece board.
• There is no 1N4148 diode for the x64 single piece board.
• I received 25v22u capacitors rather than 16v47u, and confirmed that they are correct.
• When soldering the initial 1r1 resistors, I ended up feeding half a dozen of them through the wrong holes on the transistor side. Take an extra moment to ensure that the resistors are directly beside the 3-hole transistor location.
• Quite frequently when soldering small beads of solder would fly off and stick somewhere on the board, typically on the spirals. I'm sure this isn't a surprise for any experienced technicians but I had to remind myself to look over the board for these little things and brush them off.
• When performing the power test, my readings were a little different. I got ~7ma on one of the two resistors, and zero on the other. I saw 5V and 2V on the top right diodes as described. I later discovered a few posts that weren't soldered, so this may explain the different current reading.