K2 Hi Cur

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K2 Hi Cur

Bo Andersson
Hi!

After building and installation of K60XV, I got problem with Hi Cur when testing transmission.

All around K60XV, as receive and settings for transverter acts as exspected.

Regardless if I set Power to 0,2 or 15 Watts or changning Cal Cur, I got Hi Cur and I can see on may power supply, radio drawing 3,5 amp.

I make some test from K2 Manual appendix E, Troubleshooting

Page 13 around ALC     Power Control Test VPWR reading was 1.10 VDC Expected 0.7 - 2.5 VDC, no problem

Page 14 Pre-Driver, Driver and PA

Driver Input Reading: 1.71 Vrms Expected: 0.026 Vrms
Driver Output Reading: 0.416 Vrms Expected: 1.8 Vrms
PA Input(Q7) Reading: 0.8 Vrms Expected: 0.38 Vrms
PA Input(Q8) Reading  0.39 Vrms Expected: 0.38 Vrms
RF Detector Input Reading  0.4 Vrms Expected: 2.0 Vrms

It seems that one or both PA transistor could be defective.

Measure Diode/Transistor as point 7.

+ = positive lead to
-  = negative lead to

Q7

B C E
+ 0.68K 0.68K
- 6.0k 0.85K

Q8

B C E
+ 0.68K 0.68k
- 6.0K 0.85K

I hope some one can read and understanding my measure and perhaps have an idee around this problem.

73's Bo/SM6FPG
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Re: K2 Hi Cur

AD6XY
How are you measuring those voltages? In any case, it looks like the driver is not working. You will have installed a nylon standoff on it, I would look for a short around that area.

Mike


Bo Andersson wrote
Hi!

After building and installation of K60XV, I got problem with Hi Cur when testing transmission.

All around K60XV, as receive and settings for transverter acts as exspected.

Regardless if I set Power to 0,2 or 15 Watts or changning Cal Cur, I got Hi Cur and I can see on may power supply, radio drawing 3,5 amp.

I make some test from K2 Manual appendix E, Troubleshooting

Page 13 around ALC     Power Control Test VPWR reading was 1.10 VDC Expected 0.7 - 2.5 VDC, no problem

Page 14 Pre-Driver, Driver and PA

Driver Input Reading: 1.71 Vrms Expected: 0.026 Vrms
Driver Output Reading: 0.416 Vrms Expected: 1.8 Vrms
PA Input(Q7) Reading: 0.8 Vrms Expected: 0.38 Vrms
PA Input(Q8) Reading  0.39 Vrms Expected: 0.38 Vrms
RF Detector Input Reading  0.4 Vrms Expected: 2.0 Vrms

It seems that one or both PA transistor could be defective.

Measure Diode/Transistor as point 7.

+ = positive lead to
-  = negative lead to

Q7

B C E
+ 0.68K 0.68K
- 6.0k 0.85K

Q8

B C E
+ 0.68K 0.68k
- 6.0K 0.85K

I hope some one can read and understanding my measure and perhaps have an idee around this problem.

73's Bo/SM6FPG
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com