Kenwood TS450s - UK Vintage Radio Repair and Restoration Discussion Forum

g0hze snowy · 3rd Apr 2017, 3:27 pm

Hi All, some advice please, I have recently purchased a Kenwood TS450s that has no RF out and the ALC appears to be non functional, I cant make out if the ALC is working flat out or not at all, the lower bar-graph is full over, is that pertinent?.
So far I have replace C104 ( Audio cap) and remade several blackened plated thru' holes.
Uses some small amount of additional current when TX button pressed, the fans drawing that little extra current I suspect.
The auto tuner motors don't move when the button pressed
I have replaced the memory battery as it looked as if it had leaked, no apparent damage to the control board.
thanks
Snowy

HamishBoxer · 3rd Apr 2017, 3:44 pm

I have downloaded the service/operating and mods manual if any good to you? Back on pc shortly.

g0hze snowy · 3rd Apr 2017, 4:48 pm

Thanks for the offer, I have done the same, going to attempt to print them later,Snowy

Radio Wrangler · 3rd Apr 2017, 6:22 pm

That family have a bit of a reputation for soldering going bad around the PA transistors.

But as you've just bought it, you don't know what anyone's done with it. So the first step is to look for RF drive and DC power going to the PA board.

David

g0hze snowy · 3rd Apr 2017, 8:50 pm

Thanks for the advice R/W, will look for that tomorrow AFTER I clean my trike as the chap coming to see it Wednesday.Snowy

g0hze snowy · 4th Apr 2017, 4:08 pm

Hi, Update: Have put my meter across the PA and driver trannies, all seems well with those so I checked the drive, it seems that I don't have any drive to the PA board, this is perhaps why the auto atu doesn't fire up, if there is nothing coming out then it can't match it.
so probable fault on the IF board, more delving required.Snowy

G6Tanuki · 4th Apr 2017, 5:25 pm

Is the fault still present if you operate in CW mode?

g0hze snowy · 4th Apr 2017, 7:18 pm

Hi, thanks for your response, the fault is apparent in all modes I'm afraid.
If you are familiar with this radio then can you tell me if the alc indicator is in the form of a bar graph on the lowest point on the display, this radio is new to me so I am not sure on the indicators at the moment.
If, and when I fix it then I will be looking for a 250hz cw filter for it.
cheers
snowy

3rd Apr 2017, 3:27 pm	#1
g0hze snowy Hexode Join Date: Oct 2013 Location: Peterborough, Cambridgeshire, UK. Posts: 336	Kenwood TS450s Hi All, some advice please, I have recently purchased a Kenwood TS450s that has no RF out and the ALC appears to be non functional, I cant make out if the ALC is working flat out or not at all, the lower bar-graph is full over, is that pertinent?. So far I have replace C104 ( Audio cap) and remade several blackened plated thru' holes. Uses some small amount of additional current when TX button pressed, the fans drawing that little extra current I suspect. The auto tuner motors don't move when the button pressed I have replaced the memory battery as it looked as if it had leaked, no apparent damage to the control board. thanks Snowy

3rd Apr 2017, 3:44 pm	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,935	Re: Kenwood TS450s I have downloaded the service/operating and mods manual if any good to you? Back on pc shortly. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

3rd Apr 2017, 4:48 pm	#3
g0hze snowy Hexode Join Date: Oct 2013 Location: Peterborough, Cambridgeshire, UK. Posts: 336	Re: Kenwood TS450s Thanks for the offer, I have done the same, going to attempt to print them later,Snowy

3rd Apr 2017, 6:22 pm	#4
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,901	Re: Kenwood TS450s That family have a bit of a reputation for soldering going bad around the PA transistors. But as you've just bought it, you don't know what anyone's done with it. So the first step is to look for RF drive and DC power going to the PA board. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

3rd Apr 2017, 8:50 pm	#5
g0hze snowy Hexode Join Date: Oct 2013 Location: Peterborough, Cambridgeshire, UK. Posts: 336	Re: Kenwood TS450s Thanks for the advice R/W, will look for that tomorrow AFTER I clean my trike as the chap coming to see it Wednesday.Snowy

4th Apr 2017, 4:08 pm	#6
g0hze snowy Hexode Join Date: Oct 2013 Location: Peterborough, Cambridgeshire, UK. Posts: 336	Re: Kenwood TS450s Hi, Update: Have put my meter across the PA and driver trannies, all seems well with those so I checked the drive, it seems that I don't have any drive to the PA board, this is perhaps why the auto atu doesn't fire up, if there is nothing coming out then it can't match it. so probable fault on the IF board, more delving required.Snowy

4th Apr 2017, 5:25 pm	#7
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,007	Re: Kenwood TS450s Is the fault still present if you operate in CW mode?

4th Apr 2017, 7:18 pm	#8
g0hze snowy Hexode Join Date: Oct 2013 Location: Peterborough, Cambridgeshire, UK. Posts: 336	Re: Kenwood TS450s Hi, thanks for your response, the fault is apparent in all modes I'm afraid. If you are familiar with this radio then can you tell me if the alc indicator is in the form of a bar graph on the lowest point on the display, this radio is new to me so I am not sure on the indicators at the moment. If, and when I fix it then I will be looking for a 250hz cw filter for it. cheers snowy