JHS Pollinator issue - wont stay on

[vanboylan]

Hi guys,

My friend has given me his JHS pollinator to look at - when attached to a power supply it turns on for about a second and then powers down, powers up again, powers down etc. I'm running it off of the correct power supply, and JHS advised me it could be the MAX1044 (or equivalent) chip in the voltage inverter part of the circuit. I'm awaiting an order of these so I can replace and test it, but I assumed it was probably a bad capacitor that couldn't hold power.

Does anyone have any experience of this kind of thing happening? I'm 100% sure this is something on the circuit - it's not a busted wire or anything.

Any help would be appreciated!

[Andrekp]

Start with the obvious:  Make sure it's not the physical DC jack.  I've never had the problem, but Mark Hammer recently raised the issue of some of his jacks not working correctly.

I've got nothing beyond that, sorry.  Good luck.

[bartimaeus]

MAX1044's are fairly delicate, so it makes sense that that might be the culprit. Have you opened it up to see if any caps looks visibly damaged, or are disconnected?

[mth5044]

Have you tried opening it up, taking voltages? See where the power fails. Is there a short causing the power supply to trip, or are you getting a steady 9V in and something inside is cycling?

[vanboylan]

Hi guys thanks for the input.

I replaced the 1044 with a 7660s and the on/off cycle is exactly the same.

I plugged it in ad checked the voltage from the DC barrel jack itself and it seems to go from full voltage to 0 every couple of seconds - I tested the disconnected power supply and it offers steady voltage when not connected to the pollinator.

When I'm home I'll test it with and fresh barrel jack and see how that goes. Thanks for your input guys.

Side note - I didn't get any emails to let me know you'd replied so apologies for the delay

[antonis]

Veeeeeeeeery leaky PS filter capacitor, perhaps..??

[bluebunny]

I plugged it in ad checked the voltage from the DC barrel jack itself and it seems to go from full voltage to 0 every couple of seconds - I tested the disconnected power supply and it offers steady voltage when not connected to the pollinator.

What power supply is it?  Some clever ones (e.g. 1Spot) will turn themselves off if they detect a short circuit (i.e. over-current).  A while later they will switch themselves on again to see if the fault has passed.  This cycle repeats until all is OK.

[antonis]

Some clever ones (e.g. 1Spot) will turn themselves off if they detect a short circuit (i.e. over-current).  A while later they will switch themselves on again to see if the fault has passed.  This cycle repeats until all is OK.

So they hope to some miracle, like self-healing...

[vanboylan]

Sorry for the lack of response - I replaced the power jack, no change. I replaced the power filter capacitor (100uf) to no avail.

I'm absolutely stumped with this! Any more ideas? I really appreciate everyone's input

[mth5044]

I plugged it in ad checked the voltage from the DC barrel jack itself and it seems to go from full voltage to 0 every couple of seconds - I tested the disconnected power supply and it offers steady voltage when not connected to the pollinator.

What power supply is it?

^^^

Check the resistance or continuity between your + power input and ground without the power adapter plugged in.

[vanboylan]

I'll check that power momentarily. It's just a standard 9v power adapter. I was using an official boss 9v adapter but when I tested that it was kicking out 18v! Luckily the rest of my pedals seem fine on it but it was very confusing

[bluebunny]

I'm guessing that was a Boss ACA adaptor.  It's unregulated and will put out plenty more than 9V when not under load - hence your reading.  The more modern PSA adaptor is regulated and gives 9V no matter the load.

[vanboylan]

Excellent knowledge there - it's pretty old, but got it as part of a Gumtree multi buy - £77 for a boss bcb60 with power supply, boss chorus, axiom delay, zoom modulator multipedal and some shit rocktek overdrive. Not a bad deal but I'm glad I got a replacement power supply now haha

[vanboylan]

So - I have continuity between them. I don't know where this is occurring and wondering if you might have any thoughts?

[thermionix]

I'm not familiar with the circuit, but good chance it has a polarity protection diode, which may have shorted when someone hooked up reverse power.  That's the first thing I would look for.

[vanboylan]

UPLATE - I tried that polarity protecion diode and that was the issue! I'm pretty annoyed JHS didn't suggest checking that but I'm just glad it's all sorted.

Pretty irritating the first thing they suggested was to change the chip out. That was such an irritating job!

Thanks for all your help guys