Today I tried to use one of the c5's that until now had worked faultlessly, when I engage the power it goes for a few seconds then cuts out with the lights in the left hand side of the pod flashing, if I kill the power and try again after a minute or so it's away again but only for a few seconds and dies with all of the lights on the left flashing? Any advice would be appreciated. Cheers Ad

Unfortunately this sounds like a fault with either the POD ULA chip or the LM358 op amp chip in the control box.

The LM358 is fairly easy to get a replacement, however the POD ULA chip isn't available anywhere other than another POD.

As you have several C5's Do you have 1 that is currently working? If so can you swap the POD's around, that will at least let you know if the POD is faulty or the control box.

A while back I did make a POD ULA replacement board that simulated some of the ULA's original functionality which is described here.

Cool mate, I tried the pod from one of the others and it still has the fault. Is it common for faults to develop like this? Also I fitted a key type kill switch in line with the black wire that feeds to the rocker switch, could that possibly cause a issue?

Also Dan, if it turns out to be the chip in the control box, is it possible to pull the chip from another and try or is it a case of changing the whole board in the box?

Hi Ad,

It's looking likely that its the control box then (unless both pods aren't working) As the electrics in a C5 are approaching 30 years old, it is fairly common for faults like this to occur, I have a POD that has flashing LEDs myself, though in my case I know the ULA is broken

Your kill switch is unlikely to have any effect on it, I'd suspect the LM358 in the control box. As you have a large number of C5's to repair I'd guess a few of them will have electrical problems in both POD/control box.

When you come to looking at the POD during the restorations its a good idea to check the connector pins at the back are clean and there are no broken solder joints on the POD PCB, these are fairly common. Check none of the resistors are burnt out, this can happen as well.

Also Dan, if it turns out to be the chip in the control box, is it possible to pull the chip from another and try or is it a case of changing the whole board in the box?

You can yes but it may be tricky as the chip is soldered straight to the PCB. You can pick up a bunch of 10 LM358's off of ebay for about £3.

If you do remove them it's worth putting in a socket so you can easily change them in the future. I also posted this modification which can enhance the life of this chip.

As for the POD ULA chip, this is thankfully in a socket and you can freely interchange this chip with other POD's. Just be careful of static discharge damaging it

I got 3 ula chips spare dan 1 I got from u and 2 than drop on battery side turn off turn on full again

Got some serious pod-problems too... Thinking about it... :-(
The worst part is, that my failure happened on the first testrun of the ULA, the motor then started to fail and the electrics started smoking,.. Not good...