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void kryo 5.5 / ram s4004 problem

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Forum Name: Electro Frying Forum
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=84399
Printed Date: 29 March 2024 at 3:24pm
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Topic: void kryo 5.5 / ram s4004 problem
Posted By: cravings
Subject: void kryo 5.5 / ram s4004 problem
Date Posted: 07 January 2014 at 6:34pm
had one of these out on new years. have used this amp many many times. have used it bridged into subs the odd time... it's always surprised / impressed me with how well it's done...


but on new years it was running a pair of bi amped martin W3. the easiest job i've ever asked it to do.. and it failed. got a call from the venue saying the tops were off. got there and found the power light on the amp blinking. disconnected speakons, tried again.. same. everything else on the same outlet working fine (matrix xt6004, dbmark crossover and full set of dj kit). had a spare 2 channel amp with me but couldn't get it to run the martins how things were all set but got a pair of mismatched tops on sticks going but was disappointed because i was pleased with the martins...

anysay.. today in the workshop, this amp seems fine. so do the speakers. have gone over all the speakon leads for shorts, nothing. all good. have read the amps manual on protection etc, no description of this. didn't go into temp or protect mode, just shut off with this led blinking.

cleaned it out today. bit dusty alright but both fans spinning and airflow pretty clear.

anyone any thoughts? can't trust it now..



Replies:
Posted By: kedwardsleisure
Date Posted: 07 January 2014 at 7:52pm
Check for pcb flashover around the emitter resistors; the pcb lands are very close here and can flash over under humid conditions



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Kevin

North Staffordshire



Posted By: Wrighty
Date Posted: 08 January 2014 at 1:31am
I don't know this amp and Kev may already be spot on with his suggestion, but here's another...

Low supply voltage and a more sensitive PSU than the other gear running from the same outlet, maybe...? We did a job a few years ago, running off a customer-supplied genny (which was well within spec and a decent unit). Part way through the evening, the 4 Sennheiser radio mic receivers started to randomly go off and on, shortly followed by the Crown XTi powering the tops. We managed to get through the evening with wired mics and an old C-Audio ST600 with a less sensitive, linear PSU. We didn't have a multimeter with us, but low voltage was definitely to blame in this case, as the dimness of the lights in the tent indicated and the genny engineer confirmed the next day!

If you've got access to a variac, it might be worth trying it on that, to see if you can repeat the symptoms with low voltage.


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ALL YOUR BASS ARE BELONG TO US.


Posted By: cravings
Date Posted: 08 January 2014 at 2:34am
Originally posted by Wrighty Wrighty wrote:

If you've got access to a variac, it might be worth trying it on that, to see if you can repeat the symptoms with low voltage.


good point, i do, i will.

i've done stuff in this venue for the last year and a half with no power problems. it was a small setup really. i'm almost certain i've used that same amp there before without issue.

thanks for suggestions. tomorrow i'll have another look at what i can see of the amp channels. it's a small package with a lot in it.

here is ram's own pic of the internals.



as said, i'll have a look tomorrow for any signs of pcb damage, and will see how it behaves on the variac. thanks again.


Posted By: odc04r
Date Posted: 08 January 2014 at 10:02am
Do you mean a 5.4 amp? Or is there another model I forget? If so I have managed to kill one before by running just a 8ohm bass load on one channel (not even 2 bridged!) and a couple of tops on another 2. I'm not convinced the power in the venue was the best (lights used to flash a bit) but can't say for sure if that had anything to do with it.

Chris (Ceharden) repaired that for me at the time so he has a fair bit of experience with the 5.4 model.


Posted By: cravings
Date Posted: 08 January 2014 at 11:44am
well it does say 5.4 on the front of the amp.. but if you look through all of voids manuals etc, they reckon they made a 4.5 and a 5.5..

but yeah the bigger one.

amp is seemingly running fine now, just gave up while on the job..

in the workshop soon so will look at it a bit more. curious to hear chris' experience with them so.


Posted By: odc04r
Date Posted: 08 January 2014 at 12:35pm
My one went bang nicely, from memory Chris thought the PSU had gone faulty on one rail. Didn't damage any drivers though. Took a while to die too, sound went a bit wonky for 30 seconds and then there was silence and a bad burning smell... At which point it was quickly turned off!


Posted By: ceharden
Date Posted: 08 January 2014 at 9:55pm
I'm afraid my memory of it is a bit hazy, was a fair while ago.  I know I definitely had to repair the surface mount plug-in driver board for the switchmode power supply and I think the output stage on one channel.


Posted By: kedwardsleisure
Date Posted: 09 January 2014 at 12:42pm
The muck accumulates in between the fans and the heatsinks. You can lift the fans out and then examine the board there.

A flashing external power light indicates a tripping power supply which means something is loading it down., the internal power light stays lit.
Under/over voltage will normally just shut it down completely.

Another intermittent fault can occur where the secondary bus caps wear out, check if any are bulging, it may work at room temperature but trip if its in a cold venue. The secondary caps sit behind the speakons and are marked 'SamYoung'.



-------------
Kevin

North Staffordshire



Posted By: cravings
Date Posted: 10 January 2014 at 2:36pm
put it on my variac this morning. i have my variac set up permanently in series with a light bulb.. do intend on making possible to bypass the lamp but haven't done it yet.

but yeah, on the variac, the lamp glows very brightly. brighter than i've seen it before i think.

and also, it doesn't power up properly while on this setup. the power light goes on and off and the fans start up and shut down.. it seems like a much slower flashinf cycle than i saw in the venue though. maybe about 2 seconds between on and next on, in the venue it was much more like 4 times that. flashing / starting up sequence didn't change between about 210v and 240v.

have it open now, and the fan board out. i cleaned all the gunk out the other day.. there was a good bit but not too much.

can't see anything visibly out of order.. those caps look fine, nothing looks visibly scorched or anything.

i'll continue checking what i can but this one may be beyond me (most are beyond me heh.)

cheers for tips.

can i disconnect the connectors that connect to the 2 pairs of channels does anyone know? white molex type ones where kevin described the flashover possible area?


Posted By: kedwardsleisure
Date Posted: 10 January 2014 at 8:25pm
I thought you said it works fine away from the venue?


-------------
Kevin

North Staffordshire



Posted By: cravings
Date Posted: 10 January 2014 at 8:37pm
well it powers up, here in the garage, and played music ok.. only ran it quietly.

but as i said above when i powered up via a series light bulb, the bulb ewent very bright and the amp didn't start up properly.



Posted By: Marko
Date Posted: 10 January 2014 at 10:11pm
how much W is the bulb?


Posted By: ceharden
Date Posted: 10 January 2014 at 11:36pm
Some power supplies won't behave when being tested using the lightbulb method.  When the amp draws current, the resistance of the lamp causes the supply Voltage to the power supply to drop and could cause it to 'brown out' and the power supply shuts down.  Current drops, supply Voltage rises, power supply turns back on and what you end up is a very expensive flashing light controller!


Posted By: cravings
Date Posted: 11 January 2014 at 1:51am
i think it's a 100w bulb.


Posted By: Marko
Date Posted: 11 January 2014 at 8:00am
what Chris said...
you can avoid this by using higer wattage bulb
but then you probably loose the point of the bulb, if something in the amp need to blow it will blow...
 


Posted By: cravings
Date Posted: 22 September 2014 at 8:39pm
just to bring this back up.. this amp went on the shelf of mistrust since new years, but as i said above it's always worked in the workshop since then. but the other day did a freebie gig for the climate change picnic thing here, so figured i'd bring it and the martin w3s again for a test run. ran them as side fills, ran them hard on live music, amp didn't miss a beat all day.. so i'm going to assume something weird about the new years' venue's power supply was the cause of the weirdness.


Posted By: cravings
Date Posted: 13 March 2017 at 6:44pm
hah. this amp has been on the shelf since then i think. today used it in the workshop as i was testing a crossover.. and it worked fine. shut it down, started it up and the power light started flashing.. googled it.. and found my own thread i'd completely forgotten about haha. sigh..

wow that was 3 years ago.. guess its' still an issue with this amp


Posted By: kedwardsleisure
Date Posted: 13 March 2017 at 8:08pm
it hasn't improved with age then, unlike alot of what comes from Spain.

There are 2 wire jumpers you can pull off to check if it's an output fault. The psu should run seperately from the output section. Discharge caps before reconnecting.

-------------
Kevin

North Staffordshire



Posted By: jumps
Date Posted: 14 April 2017 at 6:33pm
we ve had problems like the one you describe. 

And after a lot troubleshooting we got to the guess conclusion it was bad grounding. 





Posted By: jumps
Date Posted: 14 April 2017 at 6:34pm
this on normal operating condition when it was not pcb design fault and they blew up


Posted By: simonp1100
Date Posted: 15 April 2017 at 12:13pm
Had one of these a while back for repair. Both IGBT's were blown on switchmode as well as the driver chip & PWM chip on the driver plug in card and a few loose PSU caps.

As Kev has said already, the main problem with this amplifier is the very close tracks around the heatsinks hence easy for flashover and moisture to get in. Bit of a bugger of an amplifier to repair if it's not the PSU. Design was not good around this area i feel, too many tracks so close together. CryCry



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