Zetagi B300P Amp

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sickboy
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Zetagi B300P Amp

Post by sickboy » 01 Jan 2018, 14:03

I bought this amp which was supposed to be in working order, but all that happens when you try to drive it is the larger of the two relays inside it buzzes and chatters like crazy.. has anyone experienced this before and could suggest a fix?
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Re: Zetagi B300P Amp

Post by ch25 » 01 Jan 2018, 14:10

In AM?
Look for cold solder joints between vertical and horizontal PCB especially silver coil.

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Re: Zetagi B300P Amp

Post by sickboy » 01 Jan 2018, 14:14

In both modes. Thanks Chris I'll have a look later today :)
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Re: Zetagi B300P Amp

Post by pienari » 03 Jan 2018, 07:28

Cables right ant/tx ?.
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Re: Zetagi B300P Amp

Post by Tim » 03 Jan 2018, 10:33

Are you putting enough drive into it? do not put any more than 10W into it and make sure your patch leads/connections are good. Also make sure your power connection to the amp are adequate, minimum of 20A cable, also that the power source is good enough, at least 12.8V and that the Amperage that can be drawn from it is at least 40A, plus, make sure the connections at the power source are good and tight. Go from there, if none of the above cures or improves the problem then it's probable that the relay contacts are dirty and need cleaning. Also remember that these amps do not put out the full power stated, if you get 250W out you'll be doing well.

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Re: Zetagi B300P Amp

Post by 108EH002 » 03 Jan 2018, 12:19

Wouldnt put 10w in on stage six in am/fm mode,maybe ok 1-5.Most Cb 6 way switchable amps advise less input on stage 6.
You can talk worldwide on CB radio aswell = not 10 - 15 miles,
rsgb/ofcom are too far up their own @rses to admit it = snobs,
but many freebanders just happen to know otherwise = 27Mhz.

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Re: Zetagi B300P Amp

Post by astradyne » 03 Jan 2018, 13:25

108EH002 wrote:
03 Jan 2018, 12:19
Wouldnt put 10w in on stage six in am/fm mode,maybe ok 1-5.Most Cb 6 way switchable amps advise less input on stage 6.
I can't remember if it's stated in the leaflet which came with the B300 when new, or if it's printed on the sticker on the bottom plate of the linear. But it does say you should not put the maximum input power (10W FM and 20W SSB) in when using setting 6. The same is stated with my KL400.
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Re: Zetagi B300P Amp

Post by sickboy » 03 Jan 2018, 15:17

Thanks guys, It's all working now. Unfortunately I'm not 100% certain what the fix was...
I resoldered most of the joints on the vertical board, then used different patchleads, different rig and different power meter and it now works. I suspect the solder joints were the culprit though.
With 4 watts FM in it's giving me around 100w out (in position 6), then with 12w SSB it's doing around 180w out. Does that sound about right for one of these?
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Re: Zetagi B300P Amp

Post by pienari » 03 Jan 2018, 15:52

What psu voltage?.
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Re: Zetagi B300P Amp

Post by sickboy » 03 Jan 2018, 16:02

pienari wrote:
03 Jan 2018, 15:52
What psu voltage?.
13.8v
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Re: Zetagi B300P Amp

Post by ch25 » 03 Jan 2018, 19:45

Good values considering it is 2xMRF455 device.
Chris.

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Re: Zetagi B300P Amp

Post by sickboy » 03 Jan 2018, 19:48

ch25 wrote:
03 Jan 2018, 19:45
Good values considering it is 2xMRF455 device.
Chris.
Thanks for suggesting the solder joints :thumbup:
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Re: Zetagi B300P Amp

Post by 108EH002 » 03 Jan 2018, 21:13

Better just running it at stage 3 with 5 am/fm and 10w ssb upto stage 5,will last a long longer imo,just make sure mic gain is up for maximum drive ( power mic if needed ).Have owned a few b300ps and 3 rmkl 400s and they were ok,but I got them cheaper second-hand.I just use a rmkl 203p with half stated input power,had it 6 year and if it pops it is replaceable for about a third of the bigger Cb amps.
You can talk worldwide on CB radio aswell = not 10 - 15 miles,
rsgb/ofcom are too far up their own @rses to admit it = snobs,
but many freebanders just happen to know otherwise = 27Mhz.

Prefer being an IQ0 on 27.555☠

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Re: Zetagi B300P Amp

Post by ch25 » 03 Jan 2018, 21:47

108EH002 wrote:
03 Jan 2018, 21:13
Better just running it at stage 3 with 5 am/fm and 10w ssb upto stage 5
Wrong. It destroys matching between radio and amp. Always use 6 with reduced drive.

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Re: Zetagi B300P Amp

Post by 108EH002 » 04 Jan 2018, 10:49

Cheers for that ch25,couldve swore I said upto stage 5,and in another thread I mentioned to reduce the power input on stage 6.Maybe better with an atu when running an amp,then you can fool the swr meter aswell.
Last edited by 108EH002 on 04 Jan 2018, 11:59, edited 1 time in total.
You can talk worldwide on CB radio aswell = not 10 - 15 miles,
rsgb/ofcom are too far up their own @rses to admit it = snobs,
but many freebanders just happen to know otherwise = 27Mhz.

Prefer being an IQ0 on 27.555☠

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