TS-440 breakdown assistance request - UK Vintage Radio Repair and Restoration Discussion Forum

jeanyves63 · 19th May 2020, 8:23 pm

Iaorana. My name is Jeanyves and I live on the island of TAHITI in French Polynesia. Thank you for welcoming me in this forum.
I have a Kenwood TS-440S radio, when I am in AM mode my program is jerking as if I am in USB, Has anyone in the group been faced with this problem? thank you for your help Mauruuru

Google a traduit. Veuillez utiliser l'anglais dans ce forum, merci.

Julesomega · 20th May 2020, 2:50 pm

Hello Jeanyves. I was waiting for someone else to reply because I do not know much about what is inside mt TS-440, I don't often use it and and it has never gone wrong!

I don't understand what your problems is. Is the problem on receive or transmit?

I remember from the Yahoo group that the most common problem is the blue compound Kenwood used on early models to lock the VCO tuning cores. All the posts and files from the group are now on Groups.io. Join the group and everyone there will understand your problem, and will tell you the solution!

PostScript - I see you have already joined the group and are getting advice

Jon_G4MDC · 20th May 2020, 5:09 pm

I was going to comment yesterday. If I understand it is too much sideband and not enough carrier power.

The correct way to adjust is to set the AM carrier control to give about 1/4 the rated SSB peak output - without modulation applied. e.g. (~25W for a 100W PEP O/P rig)
Then increase modulation using the MIC gain until just before distortion sets in (needs a second RX). If you have a scope until you have good looking mod depth
Peak and Trough.

Depending on how the power metering works it could respond to AM in all sorts of ways. It could "kick up" with AM modulation and nothing is actually wrong.

19th May 2020, 8:23 pm	#1
jeanyves63 Diode Join Date: May 2020 Location: Tahiti, French Polynesia Posts: 1	TS-440 breakdown assistance request Iaorana. My name is Jeanyves and I live on the island of TAHITI in French Polynesia. Thank you for welcoming me in this forum. I have a Kenwood TS-440S radio, when I am in AM mode my program is jerking as if I am in USB, Has anyone in the group been faced with this problem? thank you for your help Mauruuru Google a traduit. Veuillez utiliser l'anglais dans ce forum, merci.

20th May 2020, 2:50 pm	#2
Julesomega Nonode Join Date: Dec 2012 Location: Stockport, Greater Manchester, UK. Posts: 2,106	Re: TS-440 breakdown assistance request Hello Jeanyves. I was waiting for someone else to reply because I do not know much about what is inside mt TS-440, I don't often use it and and it has never gone wrong! I don't understand what your problems is. Is the problem on receive or transmit? I remember from the Yahoo group that the most common problem is the blue compound Kenwood used on early models to lock the VCO tuning cores. All the posts and files from the group are now on Groups.io. Join the group and everyone there will understand your problem, and will tell you the solution! PostScript - I see you have already joined the group and are getting advice __________________ - Julian It's good here

20th May 2020, 5:09 pm	#3
Jon_G4MDC Nonode Join Date: Nov 2015 Location: Welwyn Garden City, Hertfordshire, UK. Posts: 2,015	Re: TS-440 breakdown assistance request I was going to comment yesterday. If I understand it is too much sideband and not enough carrier power. The correct way to adjust is to set the AM carrier control to give about 1/4 the rated SSB peak output - without modulation applied. e.g. (~25W for a 100W PEP O/P rig) Then increase modulation using the MIC gain until just before distortion sets in (needs a second RX). If you have a scope until you have good looking mod depth Peak and Trough. Depending on how the power metering works it could respond to AM in all sorts of ways. It could "kick up" with AM modulation and nothing is actually wrong. Last edited by Jon_G4MDC; 20th May 2020 at 5:16 pm.