Bogner Shiva Clicking upon power up..

welshboyo

Hi All,

I've become the very happy owner of a Bogner Shiva Combo, however, I have noticed that it has started "clicking" upon power-up from cold, it sounds like a bunch of relays getting juiced up, this only happens on 1st switch on/cold, and once its happened once, it will behave fine until it lies idle/off for about an hour, where it will then do it again (as if something is draining charge)

When it happens (when amp switched from off to Stdby)the amp (or what sounds like relays) will click/stutter for a few seconds and then the amp lights will light and the amp works/sounds fine from there-on 

I have spoken with Bogner, and they have suggested that I replace the Valve Heater Power Supply, but before I delve in to the innards to replace, has anyone else come across this before, and is replacing this power supply ( which I have ordered and received btw) a pain in the arse to do?

 

 

Van_Hayden

There's a switched PSU for the heaters if I remember correctly. Easy enough to do, it's a separate board off to one side.

welshboyo

thanks mate, thats what has apparently landed on my doorstep today with a 8 quid UPS admin charge (bought from US!!)

Are these PSU's known for this behaviour?

Van_Hayden

The only one I've had for repair had an switching fault. Switch modes can have numerous noise issues...great when they're working!

welshboyo

OK, had the amp in bits and with the chassis out I can see/hear that this clicking noise is coming from nowhere near the Heater Supply....there is an LED on the Supply board which flickers in time with the clicks...reluctant to the change Heater supply if it doesn't need changing..

Time for a tech? or am I just being picky as the amp works fine after its powered up

ICBM

Sounds like it's probably got an iffy connection somewhere in the heater circuit. The clicking may be arcing at whatever point the circuit is being broken, which might not be near the board. See if you can hear where it's coming from, that might help to find it.

I would fix it - the worst-case scenario is that it goes down in use and the valves shut down. Inconvenient if it's in the middle of a gig, and even more so if it causes the HT voltage to rise to above the filter cap rating and damages them - which it can in some amps.

Not sure why they need such a fancy power supply for the heaters, since almost every other amp seems to manage just fine with a plain old transformer winding...

Van_Hayden

ICBM;28717" said:

Not sure why they need such a fancy power supply for the heaters, since almost every other amp seems to manage just fine with a plain old transformer winding...

My thoughts exactly, it's an off the shelf switch mode, easy way to get DC heaters and power for the optos.

welshboyo

So you guys think I should replace the heater P/S? its only 2 solder points from what I can see (they have bypassed the plug-in connection and hard wired it)

 

Van_Hayden

I would - like you say it's only a couple of connections!

ICBM

Van_Hayden said:

My thoughts exactly, it's an off the shelf switch mode, easy way to get DC heaters and power for the optos.

That sounds a bit cheap and nasty.

I assumed it was something sophisticated like a standard linear DC supply with the relay to stop the HT being switched on before the valves have warmed up or something...

Count me not impressed, especially if it's causing an issue.

Van_Hayden

It got some funny looks when it was on the bench.....can't remember if there was anything fancy other than that.

rockmonster

I think mine used to click a bit on power up.

welshboyo

rockmonster said:

I think mine used to click a bit on power up.

I think this is your old one...

welshboyo

@ICBM @Van_Hayden...

 

Sorry for the constant q's guys, this heater supply has a trimpot on it but I can't see/understand what it does, do I need to worry about this or is it a case of setting it location-wise in the same setting as the old one?

Van_Hayden

It could be to fine tune the DC supply - I'd take a few measurements first or get in touch with Bogner. It may not need adjusting. It's been about 5 years since I last saw one....