Amp gurus, please help! Gallien-Krueger.

[guitarhuckster1]

I have a Gallien-Krueger SEB1200 amp that I bought new in 1989.
It has developed a problem: It won't turn on.

Does anybody have a schematic for this amp or know what the problem is? It seems like this was a common problem with this model.

I'd also need to know where to get hold of a couple of 2SK809 or 2SK809A Mosfets.


Thanks!

 

[BassmanPaul]

If one of your output MOSFETS has failed you're probably going to have to replace the entire set. They have to be matched fairly closely for reliable operation.

Paul

 

[guitarhuckster1]

They're in the power supply. The only problem with the amp is that it won't turn on.

 

[T-Bird]

Hi.

I have the schematics, but because of the move, I won't be able to locate them quickly enough.

Contact GK, they were quick to reply and sent me the schematics quickly as well.

That said, the problem most probably lies in the power amp section and those MosFets are next to impossible to find, at least quantities below 1000 . Believe me I've searched. Not lately, but obsolete parts of yesteryear won't usually be readily available later.

Hitto, oletkin Suomessa. Yksi erittäin hyvä syy laittaa sijainti henkilökohtaisiin tietoihin . Missä päin asustelet?

Ko. vahvari on prototyyppi D-luokan vahvistimesta, GKn ensimmäisestä sellaisesta. Ongelmien, mm. kallis rakenne, takia valmistus lopetettiin ennenkuin oli kunnolla edes päässyt vauhtiin.

Onnea ja menestystä korjaukseen, valmistaudu pitkään prosessiin, kuten myös mahdolliseen vahvarin hyllyttämiseen. Valitettavasti.

Terveisin
Samuli

 

[guitarhuckster1]

Contact GK, they were quick to reply and sent me the schematics quickly as well.

That's the first thing I did. They wouldn't send me the schematics for some reason and seemed to prefer to pretend that this model doesn't exist.

 

[guitarhuckster1]

Hitto, oletkin Suomessa. Yksi erittäin hyvä syy laittaa sijainti henkilökohtaisiin tietoihin . Missä päin asustelet?

Ko. vahvari on prototyyppi D-luokan vahvistimesta, GKn ensimmäisestä sellaisesta. Ongelmien, mm. kallis rakenne, takia valmistus lopetettiin ennenkuin oli kunnolla edes päässyt vauhtiin.

Onnea ja menestystä korjaukseen, valmistaudu pitkään prosessiin, kuten myös mahdolliseen vahvarin hyllyttämiseen. Valitettavasti.

Terveisin
Samuli

Terve!

Asun Kirkkonummella. Jostain syystä GK ei suostunut lähettämään mulle skemaa eikä niitä tuntunut muutenkaan kiinnostavan koko asiaa.

Pitkä prosessi tää on ollutkin. Ollaan yritetty korjata vahvistinta menetelmällä "löydä viallinen komponentti, laita uusi tilalle ja katso miten seuraava räjähtää".

Jos löydät skeman olisin hyvin kiitollinen jos voisit lähettää mulle kopion (guitarhuckster1POISTATÄMÄ@gmail.com).

terv.

Michael

 

[T-Bird]

Moi.

Outoa, mulle he lähettivät ilman sen kummempia kyselyitä ja nopeasti?? Tästä on kyllä vuosia aikaa, ja kuulemma "iso luuta" on valitettavasti kyseisessäkin firmassa lakaissut parhaat yksilöt pihalle.

Koitan löytää paperiskeman, jossain kaatuneen koneen kovalevyllä pitäisi olla skannatutkin versiot. En voi luvata pikaista toimitusta, mutta etsin kyllä.

T:Samuli

 

[Devo-lution]

Finnish seems like a beautiful language, but I cannot imagine the pronunciation. Anyhow, I don't understand a word you guys are saying .

As with the rest, I think contacting GK might be one of the best things to do.

 

[guitarhuckster1]

As with the rest, I think contacting GK might be one of the best things to do.

I did. No help.

 

[BassmanPaul]

You may well have to find a suitable substitute. On three FET amps I worked on I found a viable device among International Rectifiers IRFP series. You will have to buy quite a few more than you need so that you can match them into sets. I needed sixteen per stereo amp and I bought 100. That gave me enough for eight matched sets of eight.

Paul

 

[busta_bird]

I did. No help.

I've had terrible customer service with GK in the past as well. Just keep trying and hopefully you'll get somewhere with them. My local service center did nothing but complain about their customer service as well. He waited 3 weeks for a schematic (with me calling every other day as well).

 

[guitarhuckster1]

Just keep trying and hopefully you'll get somewhere with them. .

Talkbass member T-Bird sent me copies of the schematics today.

 

[BbbyBld]

Finnish seems like a beautiful language, but I cannot imagine the pronunciation. Anyhow, I don't understand a word you guys are saying

I used google translator and just pasted the text in. It's kinda funny because you can basically tell what's being said, but some of the words don't translate correctly. Highly recommended.

 

[jackcheez]

Wut about the fuse ?

just thought I'd throw that in there.

 

[basscheez]

Robert Gallien used to post here, I think his screenname is "rag". Maybe IM him?

<edit>
Just double-checked, he's still around as of a week ago.

 

[guitarhuckster1]

Wut about the fuse ?

just thought I'd throw that in there.

Blown and replaced a number of times.

 

[FreaqyFrequency]

I used google translator and just pasted the text in. It's kinda funny because you can basically tell what's being said, but some of the words don't translate correctly. Highly recommended.

Not to turn this into a thread about Finland, but I've been learning Finnish since about May of this year from my girlfriend, whose mother was born in Heinola and lived in Savonlinna for years. I could tell you a majority of what they're saying, though not all.

You're out of luck with the translator if you're trying to translate a different dialect, such as Savo or Karelian (Karjalainen). I've put my entire computer into Finnish and set my homepage as Ilta-Sanomat (Evening Times), so that I can be immersed into it. It is indeed a cool language.

@Devo-lution: The pronunciation is just as it reads in Finnish. All of the letters have one sound, and if the letter is doubled, you hold the sound for just a bit longer than normal.

The Finnish alphabet is identical to the English one, with an ä, ö, and å (Swedish/Norwegian/Danish letter) at the end of the alphabet. J is a "yuh" sound, and y is the same as the ü in German. Exactly the same, otherwise.

Back on topic: So GK sent you nothing helpful in return? That is odd indeed. I hope you are able to resolve the issue soon.

Terve ja paljon onnea Yhdysvalloista!

(Suomea on paras kieli, myös. )

 

[BassmanPaul]

Getting back to the original topic, I have found the 2SK809 is available via a google search. Minimum quantities I didn't look into. I believe that the IRFP254 would be suitable for the service in the power supply. I have ten that are matched to within a few hundredths of a volt. If the OP and Sam would like to PM me with their addresses I'll send you a couple each. This, of course, assumes that the power supply is the actual problem area.

Paul

 

[FreaqyFrequency]

It seems possible that it could also be an issue with the switch, which would be a much easier fix than replacing either individual bits or the entirety of the power supply.

Still, it seems odd that GK wouldn't be helpful, considering that they have a decently large base of customers. Customer service ought to be paramount to a company in their position.

 

[guitarhuckster1]

Update:

I found a source for 2SK809s. Invalid Link Removed

The minumum order was 10 which is not that bad. They didn't cost very much either. Should be here in a couple of weeks.

We think that we found the original problem (Not the switch. That was the second thing we checked after the fuse). Which would have been easy to fix. The blown 2SK809s are a consequence of trying to repair the amp without a schematic.

I was also surprised (and a bit peeved) about Gallien-Kruegers customer service. Especially compared to Hartke. It already cost G-K a sale. I was going to buy another rig anyway and was considering G-K as one of the alternatives. I bought a Hartke LH500 and a HyDrive 115 after my experiences with both G-Ks and Hartke's customer service.