I would appreciate any opinions and info on IC-746 (non pro) operation, and which optional filters have various users found to be best...I find a lot of adjacent channel interference on SSB when using this radio...Have others experienced this??? I know there are many combination of both 9MHZ & 455 khz filters available...I would like to hear opinons about which filters they installed, and what the results we're...And lastly with the double pass band tuning, is this in essence doing what a filter would do in narrowing down the pass band??  If so, then why are filters necessary at all...Please enlighten me...

Good Morning All...I have never met Cliff in person, but have had the pleasure of talking to him on the phone twice...I say the pleasure because on both occasions he helped me with a minor problem...he's a fine gentlemen,and a Kenwood expert and I believe most of us who are out here recognize that fact..
   Keep up the good work Cliff...73/BOB

I have experienced a similar problem on my 200 on and off for years, and cleaning the relay contacts has always cured the problem..I just run a sheet of paper that I wet down with contact cleaner through the relay contacts, while applying a little pressure to make sure they make contact with the paper I am sliding through..
   In my experience when I first start to hear the signals decreasing, keying the mic on and off three of four times always confirms the condition, as without fail as I key the mic, the signal will alternately come back with the proper signal strength(hope I made that clear)
   If you do open the amp, as per a previous post, CAREFUL is the key word...early on in my radio experience I found out first hand what 3000VDC feels like...Good Luck...BOB

If indeed the mic was wired correctly for the 440 by the gentlemen you purchased it from....

Hello to all...Well I started this thread about four months ago, and I have found the solution...I finally located a set of CETRON 572B-s (I WOULDN'T HAVE THAT CHINESE JUNK) As soon as the new set of tubes was installed, the problem of not enough range in the loading control all disappeared...Obviously the reason for the problem was that in order to try and get the power I desired from the old tubes that we're not capable of putting it out, I was trying to load the amp more and more until the load control was at its CCW stop. Now I have removed that extra capacitance that I had advocated adding in the 80 meter position, and replaced the original 500mmf cap, and all is well.. I have a feeling that this might be the problem with many who are experiencing the same problem...COMMENTS???

I have some AMPHENOL PL-284/83--22SP/UG-102/U
connectors...are these the ones used for the R-390A antenna connection...BOB

Give Cliff at AVVID a call(he's in the review section under amateur radio repair)...He is one of the most knowledgeable KENWOOD repair people I know, and one of the friendliest.  He will steer you in the right direction.  Incidentally I own a 130S, and I agree its a great radio..Good Luck..BOB

Greg....This is K2LGO...I started this thread...email me at robco@optonline.net and I'll tell you what I have that you can have that should work..BOB

SHUT THE RIG DOWN, AND TAKE OFF THE TOP COVER, AND TIGHTEN DOWN ALL THE SCREWS THAT HOLD THE CIRCUIT BOARDS TO THE CHASSIS..ESPECIALLY THE BOARD BELOW THE BANDSWITCH ASSY...YOU MIGHT ALSO TRY CLEANING THE BANDSWITCH CONTACTS WITH SOME GOOD QUALITY CLEANER...GOOD LUCK..

WD8PHW...Please let me know if that does cure the problem...maybe its a design flaw, and most are satisfied to operate with the load control fully CCW.
                                      BOB

Steve...grid current is about 100ma and does occur at plate current dip...you can see from one of my blurps that a 1000uuf in place of the 500 padder as per the scan I sent you solved the problem, still not sure why.  The exciter is a 746(non pro) and it appears that the drive on 80 is about the same as on other bands, as indicated on the PO indicator on the 746.  Thanks for the tutorial on the relationship of drive to the need for more C when under driving occurs.  Always something to be learned..

Dick...They used a 500uuf padder, and I'm sure it has worked in the other 50,000 (give or take 10,000) SB-200-s, but for some reason it was a problem with my amp...I too would love to know if others have experienced this same problem, or if it is unique to my amp, because of some other component deficiency that I cannot uncover...BOB

PROBLEM SOLVED...For what ever reason the 500uuf padder cap in the 80m loading configuration, was not large enough...replaced with a 1000uuf, and everything fell into place...WHY...I'm not sure...I went over everything three times as per AD4U suggestions, but all was wired correctly, so I gave the 1000uuf cap a shot, and it solved the problem on 80 & 40, and the other bands are fine...if something is going on with the dual 437uuf loading variable, I damn sure can't find a problem..So hopefully alls well that ends well.  
   Thanks for all the knowledgeable fellows who took a shot at it...no place like EHAM....BOB

Whooops....I thought it was only on 80 meters, but now that I have taken the time to try 40, its the same on 40 (20 is fine) so obviously those padder capacitors have nothing to do with it...On 40 I can get 600 out (WATERS 334 WATTMETER-DUMMY LOAD) but its with load C at max(fully counter clockwise)...back to the drawing board...BOB

Lest I forget I did indeed take KB1LKR advise, and am using lower case to make reading easier...AD4U thank you for the suggestions...I have tried almost exactly what you have suggested, and I even tried tack soldering the padder cap (500uuf) in the circuit to go around the switch that switches it in, and out on 80M...I did not build this amp, but only recently started to use it on 80, so I just recently noticed the problem...I notice that the tuned input coil on 80 has very little influence on the SWR between the driver, and amp when I try to make an adjustment on 80...Could I possibly not have enough drive on 80