Zetagi B300P. A little help please.

I just got one of these Zetagi B300p amps.

After a couple of days use attached to my expanded Grant 2, Sirio Gainmaster 5/8 and 30A PSU the Pre Amp seems to have stopped working. It seems to attenuate the signal when turned on. The unit also smells as if it's burning.
For the moment I have disconnected it, I don't want to damage it or my homebase.

Does anyone have any experience with this brand?
I was under the impression that Zetagi products were O.K.

Getting a little desperate!

Hi Simon,

Did you buy the Zetagi's new or second hand?

The reason for asking is, if new from a supplier then you have a recourse of action.
If second hand then you might as well have played eenie-miney with a line of hookers - you don't know who's had their dirty paws on it or what they've done to them!

(Joking aside)

If you purchased new you can go back to the supplier and work with them. I know some will fob you off but most have a good reputation to keep and will do their best to help you. At best you'll get replacements, at worst they may charge you for repair, only some will stubbornly refuse to work with you.

If second hand then you obviously need some kind of service or repair.
Do you have appropriate equipment and skills to attempt a repair yourself? There's a tonne of information, (handy nowadays), on the internet with circuit diagrams etc.

Otherwise asking online for suggestions to repair is akin to closing your eyes and putting your fingers in your ears whilst stomping across a minefield.....if you're very lucky you might get across!

The usual fault with this type of equipment is people over driving them, however other faults can occur too.

To me it seems like the preamp transistor, (or transistors depending on design or version), has blown obvious by the preamp function appearing to fail. The "burning" smell would have me concerned that there's maybe something more at fault.

As for the Zetagi brand, they have manufactured and or branded equipment for years.
That's a bit like asking the "Nike/Reebok/etc." question, a personal preference if you will.
At this moment the brand doesn't seem all that good for you, but for others who have never had a problem with the brand will give it all thumbs up.


I'd say you did the best thing by simply disconnecting them and protecting your rig.

From here on in is up to you. Bin them, send them for repair, or attempt a self repair.


I feel for you, it's disheartening when a piece of equipment fails, but at least it wasn't your rig - that really sucks!


Best of luck,
Victor

Sounds as if the preamp side has got fried. If the TX/RX relay hasn't switched over and it's applied TX power to the preamp, that could be one cause of the problem. Assuming it's only cooked the preamp transistors (which are cheap enough) it's not a big repair for someone who knows what they are doing.

Thanks 26CT62.
Sounds interesting.
Think I'll have to take it to the shop to get diagnosed.
I hope it's not because my Grant 2 is too powerful for it. Supposedly kicks out 20w on SSB which is the advertised input wattage for that amp.
Noticed it's got a slight rattle too.
Hey ho!
Won't be hilltopping with it this week.

Thanks Victor.
Some very sound advice.
I will work either the retailer every time.
I could take it apart and attempt the repair however im not great at that stuff. I can do the basics, soldering but that's it.

No worries Simon,

Hope you get the issue solved, right downer when radio kit goes down.

Also, congrats on knowing uncertainty of self repair.....CBers and Hams can be notorious "screwdriver experts"!


All the best,
Victor

First of are you100% sure you radio is putting out 20watts when you are using the amp and not more , second it actually says on the information sheet inputv1w to 20w but that doesn't mean run it at 20w constantly, it means up to 20w ,I've had one for years and I have never ran at 20w constantly I've only done that on certain accations and only a short time ,as for the preamp side TBH there crap mine sometimes don't work but TBH a preamp only brings in what it hears thats including all the interference and any other crap it does not just pick out the voice transmission.

Nice one Nubster. I don't seem to have a power reducing switch like some rigs so I must have been banging in the full 20w.
Complete Nube mistake and it's a self inflicted injury! Oowwcchhh. I'm going to ask the shop to either turn my power down some on the rig or fit a switch or get an attenuator separately if it exists so I can run it barefoot if hilltopping.

Embarrassed by my stupidity, but lesson learned.
Cheers.
73.

No worries Dogfish glad to help

Update.
Got the amp repaired, cost £35 which is more than reasonable I think and it came back with a spare transistor.
I went through my patch leads and found a dodgy one, repaired it and all fine now.
Thank you all for your help.

Nice one Simon

That was an awesomely good price for a repair too.

All the best to you mate,
Victor