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 MRF 497. ( 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 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
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,
Due to a technical error, innacuracy 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
wattmeter 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.