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51 super Rockmite low voltage on collector of q3 on transmit.

KQ8B, Robert
 

Hello folks. Building a chinese 51 super rockmite, cant get the wattmeter to move but hear the signal on my other radio. Test voltages with digital volt meter and everything checks out ok according to the instructions but q3 collector voltage drops from 12v to 2 volts. Any tips would be appreciated. Thanks, Robert N4SWD

AA7US
 

Robert,

Just to be safe, I'd recommend you get a "second opinion" using a different wattmeter.

I suggest this because a couple months ago I assembled a CS-40 transceiver and was only measuring 2 watts output using what I thought was a reliable, accurate, digital QRP power/SWR meter.  After pulling my hair out trying to figure out the cause of such low TX power, in desperation I tried a different analog wattmeter.  With that second meter, the TX power was 8 watts, which was within the expected TX power range considering the ~12v input power I was using.

For some reason the digital QRP wattmeter I have doesn't like the CS-Series transceivers but seems to work fine with some other types of QRP transceivers I have.

Please keep us posted.

73,

John
AA7US

---In CHINA_QRP@..., <rbishop7@...> wrote :

Hello folks. Building a chinese 51 super rockmite, cant get the wattmeter to move but hear the signal on my other radio.

KQ8B, Robert
 

Thanks, I checked it on both of my wattmeters and shows nothing. My little qrp pixie at least shows 300mwatts on these wattmeters but nothing on the rockmite.  the q3 collector voltage supposed to stay at around 12 volts on transmit but drops to 2 volts. Dont know what I did wrong.

John Clements
 

Not sure if it will help but I worked on one with a bad transformer (t1) and also had another with bad toroids, don't remember if I saw anything on the collector of Q3 at the time with either issue.  You may want to check T2 windings, or possibly a solder bridge or wrong part around Q3/Q4 area.  Download my manual which has lots of test points, o-scope patterns, mods, etc.   http://kc9on.com/ham-radio/qrp-radios/chinese-qrp-kits-2/chinese-super-rm-rockmite-aka-octopus/

73 John kc9on

KQ8B, Robert
 

Thanks so much, actually the schematic and assembly instructions were downloaded from your website before I put it together and I bought new toroids and rewound those to no avail. I don't know what I did wrong. Thanks again. 73 Robert N4SWD