kenwood 450 issue

[W2NAP]

dude that had the rig decided it was a good idea to try and load up a tin roof. needless to say it didnt work<br><br>finals are ok tuner is ok. prob seems to be in the rf board but cant seem to pin exactly where<br><br>any ideas?

[N8YX]

Any output at all?

[kc7jty]

what are the symptoms doc? Why would horrible swr affect anything other than the the rf amp strip?

[W2NAP]

no output. it wont gen any rf at all.

finals are good tho.

[W7XF]

Is the driver transistor(s) ok? Do you have receive? Also check protection diodes on xmit side.

[W2NAP]

Is the driver transistor(s) ok? Do you have receive? Also check protection diodes on xmit side.

rx is great.

if you was lookin at the sch. seems prob is around Q20 on the rf board

[W2NAP]

well got it back home.. my only option now is to replace boards on it. (rf board) with the prices people want for the damn things looks like my HF days are done.

[N8YX]

Do you have any sort of test equipment (namely, an oscilloscope) that could be used to verify whether or not the problem is related to Q20? And if so: Can the transistor be replaced?

ETA:

"Tin roof dude" should be footing the bill - one way or another.

[W2NAP]

Do you have any sort of test equipment (namely, an oscilloscope) that could be used to verify whether or not the problem is related to Q20? And if so: Can the transistor be replaced?

I had it up at a guys place he has all the stuff scopes, rf gens,ect.

we cant get that board to do anything. q24 nothing,q18,q19,q20,q21,q45,q46,q48,q26,q27,q28 nothing.

brian looked it over for several days. its like everything related to the transmit section of that board is dead. he told me last night might as well replace the damn board it wont gen any rf. it dont want to mix. everything seems to stop right at the rf board

[KB3LAZ]

Hope you get it working bro. I did like my 450 and my 850. Sold them when I funded the 756 which I do love but also miss my 850Sat QQ. <<< Will prolly have another someday but not in the near future. Ill ask around the local net when I get home to see what ppl got laying around. Prolly nada but worth a shot to see if anyone has a parts rig.

[W2NAP]

Hope you get it working bro. I did like my 450 and my 850. Sold them when I funded the 756 which I do love but also miss my 850Sat QQ. <<< Will prolly have another someday but not in the near future. Ill ask around the local net when I get home to see what ppl got laying around. Prolly nada but worth a shot to see if anyone has a parts rig.

thanks, lucky for now i still have the 430 (but not sure how long i will, guy who owns it now could pick it up any time) the 450 is so pleasant to listen to

[K7SGJ]

For what's its worth, I always start with a through visual inspection of everything. All the boards, connectors, solder connections, etc. A magnifying glass or jewelers loupe is helpful at this point. It is amazing what you find wrong that isn't the immediate problem. Ohm the fuses, too. Then, measure all of the power supply points and verify they are within tolerance. Since you have receiver action,, start taking voltage readings in the stages of the transmitter that have nothing in common with the receiver. If the transmitter was abused, you might get lucky and find something wrong in the swr protection circuit that either blew a protection device or is disabling the output.

[W2NAP]

For what's its worth, I always start with a through visual inspection of everything. All the boards, connectors, solder connections, etc. A magnifying glass or jewelers loupe is helpful at this point. It is amazing what you find wrong that isn't the immediate problem. Ohm the fuses, too. Then, measure all of the power supply points and verify they are within tolerance. Since you have receiver action,, start taking voltage readings in the stages of the transmitter that have nothing in common with the receiver. If the transmitter was abused, you might get lucky and find something wrong in the swr protection circuit that either blew a protection device or is disabling the output.

when it cools off here. ill drag it back up to the shop. (cant deal with 120F+ in there lol) not going to give up on it.