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2). Locate and remove Q132 & Q134.
3). Replace Q134 with an ECG 340 or TCG340.
WARNING!!! The leads of the two transistors are exactly opposite of each other.
[2SC2086 = BCE ; ECG340 = ECB.]
4). Replace Q132 with an MRF497. ( Be sure to use heat sink compound. )
5). Remove C132. ( no replacement )
6) Remove C112 & C116.
7). Replace C112 with an 82pf capacitor, But put the new Capacitor on the bottom of the PC board.
8). Replace C116 with an 100pf capacitor, But put the new Capacitor on the bottom of the PC board.
Click here for the Board Layout locations for the Capacitors in HR2510
Click here for the Component Layout with Cross reference for the HR2600
9). Connect power to the
radio, and following the alignment procedures, adjust the bias of Q132
to
80mA
+/- 5mA by adjusting VR112.
[ To adjust the bias
of Q132: Remove the B002 (PB-100) jumper board from the Main PCB.
Connect a
DC Ammeter (+) to TP4, (-) to TP3.
With the
radio on USB, Adjust VR112 for 80mA +/- 5mA on the DC Ammeter.
After the
adjustment is complete, Reinstall the B002 (PB-100) jumper board. ]
10). Inject a two tone
signal into the microphone of the radio while transmitting into a dummy
load.
Set VR104 (ALC) for maximum
output..
Retune VR107 (AM /FM carrier level) for Maximum.
Retune VR103 (CW carrier level) for Maximum
11). Again inject a two
tone signal into the microphone of the radio while transmitting into a
dummy load.
Spread or contract coils
L121 & L123 for the highest power out in the center of the band.
12). Replace the covers and the screws, you should now have between 50 and 100 watts on SSB.
This mod was originally written by M.T. Stacey, KC4HGH in an article
published in CQ magazine of September 1989 on page 48.
There was also supposed to be an Update in ‘73 magazine of November
1989 on page 76, Although I have never been able to
find a copy to verify it. If you have a copy, Let me know, I
would like to obtain a copy.
Copy of update by M.T.STACEY, KC4HGH
------------------------------------------------------------------------
Due to a technical error, inaccuracy in my original test
setup, the PEP power levels on page 48 of Sept.
"73 Amateur Radio " were erroneous. After revamping the test bench
equipment, and testing the new
watt meter against a Bird 43, the findings are as follows, In modified
radios, 2-3 watts carrier, and 10-12 watts
PEP average increase over the stock peaked-out radios. Therefore, the
original goal was reached, i.e. more
power with better audio and less stress in the RF output section.
I sincerely apologize to everyone who have
been inconvenienced by the original results printed.
With regards to all, M. T. Stacey.
Update thanks to: R, Madaire, Ottawa, Ontario, CANADA.
If you have any Questions or Comments, click here to E-Mail me :
