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Hi, I'd like to be able to do a full alignment as described in the service manual for radios. I have been able to do the current alignment of the finals and driver with my multi-meter but seems like I need some more equipment to do things like receiver alignment properly. As this is just a...

Hi, so things are looking better with the Deltaforce. It seems I did have a power supply problem. My PSU has a 240/120V switch on it. It had been so long since I used it I forgot that the last time was when I took it back to Scotland, so it was still on 240V. Now I'm using it in Canada this...

Or another ideal would be to use one of these resistors: Image is from here: https://www.amateurradioawesome.com/2016/12/30/the-easy-dummy-load/ The resistors are $2 each. I was thinking of maybe using a network of 4 of them on a heat sink, ideally being able to do around 200W for 30seconds.

So back to the drawing board in terms of resistor choice, glad I asked before using wire wound :) . I was thinking about this: 50 pcs 100 Ohm Carbon Film Resistor, 2W 5% Tolerance Carbon Film Resistors, Axial Lead They come in a pack of 50, so I was thinking groups of 10 in parallel is 10...

Oh dear, this is bad news. Here's the spec of the one I ordered: uxcell 5% 200W 50 Ohm Wirewound Aluminum Housed Clad Resistor Gold Tone 12cm Long by uxcell Product Name: Aluminum Resistor; Type: RX24; Resistance Value: 50 Ohm Power Rating: 200W; Resistance Tolerance: +/- 5% (J); Lead Thread...

Hi, I'm looking to build a Dummy load suitable for peaks of 200 watts. I've ordered a 200w 50ohm resistor: I'm planning to wire this to an SO-239 using some 12 gauge solid core eletrical wire. Then I was thinking about putting in it a small paint can filled with oil. Do I need to take any...

Thanks, sounds like a bit of an overhaul is in order. I'll look at doing a bit at a time. Is there a write up anywhere on how to best check the bias into the finals? Also, I'm not currently using a dummy load, just measuring power into my antenna. Would the power meter show reduced power as...

Thanks. I've tried the adjustments but still not seeing more than about 15w, half what it claims. Also still confused by the lack of change in power when the control knob goes from 50 to 100%. What's the best way to check if one of the finals isn't performing correctly? Seems like it could be...

This one seems to work well and gets good reports. It's just I noticed the power on the meter wasn't as advertised. Searching online I found a post by someone with a similar situation. Seems like they might have come from the factory with things turned down...

Meter is a Daiwa CN-100. I have a 5 watt FM HT and it shows 5 Watts.

Hi, I've got an old Magnum Deltaforce I got used about a decade ago. Recently hooked it up to a power meter (Daiwa) to see what it's putting out. Seems to be quite a bit lower than spec. Also when I turn the power knob only the first 50% seems to do anything. From 50% to 100% there's no...

You were right! I've now solved the issue! After lots of messing about I finally found the problem was the fuse which is in the radio's power cable to the battery! I knew the fuse hadn't blown because my multimeter was showing over 12V at the radio, but when I opened the little fuse holder I...

Hi, Thanks for the replies. I'll check that voltage regulator. The thing is that it was working fine for 5 months after the jump starting incident, so this may be unrelated. I don't want to send it to the Cobra repair centre because I'm in the UK so postage wont be cheap and I'm not sure...

Hi, Got some problems with my rev3 Cobra 200 which has been working great for the last year. Sometimes when I turn it on nothing happens for a few seconds, then it turns on. Then when I key the mic on high power the frequency counter and lights on front flicker on and off really fast and I...