Amp reduces gain when going from standby to operate

[TonyV225]

When you go from Standby to Operate, the relay should not be engaging. I do agree that the QSK board is likely at fault here. That's the first thing I'd be looking at, and it seems you're already on that path. That's an amp I wouldn't mind having. Good luck on it!



~Cheers~

Thats a great amplifier and it does not matter who you buy from its electronic and like anything else electronic or mechanical, Things happen or can be faulty I own Ameritron and several MFJ products and otherthan an amplifier issue which was my fault Ive never ever had a problem with any of my tuners and products. I figure thats ok if people dont like their MFJ product and if they are selling it cheap hell ILL BUY IT!!

Its unfortunate that you have a new product and whats happening is out of your control but I can tell you that 80-90% of troubles or problem were due to owner operator error like arcing a tuner because they shot a few hundred watts into the thing when tuning after jumping from 80 meters to 10 meters LOL!!!

You will love that amplifier when its straightened out and treat it good and it will last you forever!!! Exit is right in saying you are definately on the right track. Look at it this way you can just fix it yourself or screw around packing it and shipping it out and waiting to get the damn thing back while worrying about if its ok in transit from A-B. Just repair it and learn at the same time its all about the knowedge you can also get from this. Like I said it does not matter who makes a product they all can and do eventually sell a dud. Get it straightened out and enjoy it!!!!

 

[hookedon6]

I don't have any problems with MFJ stuff, but every thing I buy new from them I look real close inside it before I use it,... lots of pieces of wire, cold solder joints , ect are common.

I went to the ARRL day in the park @ MFJ this year and they put on a great meal for everyone, also 15% of anything you bought AND they paid the sales tax too

 

[Highland Ranger]

Fuses (bulbs) arrive tomorrow.

If I unplug today, will the high voltage have dissipated by tomorrow?

 

[Beetle]

Probably, but don't trust your life to a "probably". Discharge the filter capacitors, verify the voltage is down below just a few residual volts, and attach a jumper (piece of wire with alligator clips) while you're working.

Do NOT forget to remove the jumper before powering things back up.

 

[Highland Ranger]

Thanks, I'll look up how to do that

 

[Highland Ranger]

Just for posterity, from page iii (7 in the PDF) in the manual located here http://www.ameritron.com/pdffiles/AL-80B.pdf :

1. NEVER defeat the interlock.

2. NEVER remove the cover with the amplifier connected to the power line.

3. ALWAYS allow several minutes for the capacitors to discharge after unplugging the
amplifier and before removing the cover.

4. ALWAYS select the high-voltage (HV) function of the Multimeter to check the high
voltage potential. Do not remove the cover if voltage is indicated.

5. ALWAYS ground the tube anode (top metal conductor) to the chassis before touching
anything inside the amplifier.

6. ALWAYS be cautious of heat. Many components inside the amplifier operate at high
temperatures.

7. NEVER make any unauthorized component or circuit modifications to this product. The only acceptable source for modifications is Ameritron or a source approved by Ameritron. Unauthorized modifications almost certainly will increase the risk of equipment failure or personal injury.

 

[Highland Ranger]

UPDATE:

Bulbs came today by postal mail - ugh - took a week plus.

I replaced both bulbs/fuses (both tested open) - no more drop in receive so that seems to have done the trick.

SWR is flat 1.0 and set to not key the amp through the LP-100A if it goes over 1.5 so I am not expecting to have to unscrew 40 screws and change two bulbs again.

Only question - the XMT light stays illuminated when the switch is in the OPR position.

- radio and amp are NOT keyed up

- amp does not produce power and receive is fine

But the XMT LED stays lit. Maybe that's a function of the GOP-100X (grid protection) or QSK5PC (key up) boards I had added?

Any ideas?

Also, the amp easily swings from 200 to 1000 watts on AM.

I know - too much.

I've dialed down the transceiver but seems like I really need to reduce the mic gain to minimize that swing and keep the grid protection from tripping. Any thoughts there?

 

[Highland Ranger]

Response from Ameritron:
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When you have a QSK installed, the XMIT light on the amp stays on as long as the amplifier is in operate. It only puts out power when you key up the radio.