Well I went to Toledo hamfest and bought me a SB200 Got it home and one tube broken replaced tube and hooked it up and turned it on now comes my problem. When I key it up relay stays keyed even after I release my manual pushbutton. I have to turn off amp to get it to unkey I noticed when it is keyed up and I have button pushed grid around 80 to 90 ma when I release my pushbutton keyer grid goes to zero but relay still keyed. Please help I sure donot want to put this on shelf. thanks Jimbo165
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Heathkit SB200 stays keyed
- Thread starter Jimbo165
- Start date
RatsoW8
Supporting Member, W9WDX ARC Member - WD8T
Had one a few months ago come through for repair.
Look at r21 or r 22 at the base of the tubes.
Also it could be a shorted tube
The one I repaired had bad bias resistor and tube.
http://www.cbtricks.com/Amp/heathkit/sb200/graphics/heathkit_sb200_sch.pdf
Link to the schematic.
Look at r21 or r 22 at the base of the tubes.
Also it could be a shorted tube
The one I repaired had bad bias resistor and tube.
http://www.cbtricks.com/Amp/heathkit/sb200/graphics/heathkit_sb200_sch.pdf
Link to the schematic.
SB200 stays keyed
Ratso it does not have any Harbach mods I am keying it it with a homemade pushbutton through RCA plug . Wavrider amp keys up and stays keyed is there anything that bleeds off power to relay when amp unkeys or completely stops power to relay on unkey ? I will replace r21 and r22 one tube is a new china replacement and other is Cetron they light up good and while amp is being keyed by me grid 80/90 ma and 2100/2200 HV. I am doing this on bench with no radio attached yet just antenna. I have looked at schematic but will admit I am lacking in electronics for sure was a Tool & Die Maker for my career can read those type of prints with no problem but electronical whew!!!!!! Thanks Jimbo165
Ratso it does not have any Harbach mods I am keying it it with a homemade pushbutton through RCA plug . Wavrider amp keys up and stays keyed is there anything that bleeds off power to relay when amp unkeys or completely stops power to relay on unkey ? I will replace r21 and r22 one tube is a new china replacement and other is Cetron they light up good and while amp is being keyed by me grid 80/90 ma and 2100/2200 HV. I am doing this on bench with no radio attached yet just antenna. I have looked at schematic but will admit I am lacking in electronics for sure was a Tool & Die Maker for my career can read those type of prints with no problem but electronical whew!!!!!! Thanks Jimbo165
80 to 80 ma GRID current when u key?
Is this with drive applied?
Should not be any grid current until you apply RF drive, you should have some idle plate current.
I think the resistors are 33 ohm 5 watts. These are easily over heated and opened with mis tuning.
Also does the amp key when you turn power on or only after you "key" it with your home brew switch?
There are dangerous voltages inside this amplifier so if you are not experienced working around high voltage be very careful. The voltages can be LETHAL.
Is this with drive applied?
Should not be any grid current until you apply RF drive, you should have some idle plate current.
I think the resistors are 33 ohm 5 watts. These are easily over heated and opened with mis tuning.
Also does the amp key when you turn power on or only after you "key" it with your home brew switch?
There are dangerous voltages inside this amplifier so if you are not experienced working around high voltage be very careful. The voltages can be LETHAL.
SB staying keying
Wavrider it was not grid I looked back at switch it is plate that shows 80/90 ma when keyed sorry had a brain fade moment. This plate ma is with no radio hooked up just on bench but me keying up with my pushbutton switch I made and put in a pill bottle. I have checked voltage on top of tubes and its good about 2200 volts I have been extra careful with this amp always drain caps before touching anything. OK When I turn on amp relay not keyed and grid,plate show nothing HV shows 2100/2200v on meter. When I key amp relay engages grid shows 0, plate shows 80/90 ma and HV 2100/2200v and when I unkey pushbutton relay still keyed grid 0, plate 0 and HV 2100/2200v now every time I push button plate goes to 80/80 unkey it goes to 0 but relay still keyed until I turn off power and turn it back on. All these test into a antenna but no radio . I have not used a radio yet til I can get relay problem fixed with your help. Thank You for your help Jimbo165
Wavrider it was not grid I looked back at switch it is plate that shows 80/90 ma when keyed sorry had a brain fade moment. This plate ma is with no radio hooked up just on bench but me keying up with my pushbutton switch I made and put in a pill bottle. I have checked voltage on top of tubes and its good about 2200 volts I have been extra careful with this amp always drain caps before touching anything. OK When I turn on amp relay not keyed and grid,plate show nothing HV shows 2100/2200v on meter. When I key amp relay engages grid shows 0, plate shows 80/90 ma and HV 2100/2200v and when I unkey pushbutton relay still keyed grid 0, plate 0 and HV 2100/2200v now every time I push button plate goes to 80/80 unkey it goes to 0 but relay still keyed until I turn off power and turn it back on. All these test into a antenna but no radio . I have not used a radio yet til I can get relay problem fixed with your help. Thank You for your help Jimbo165
The amp only stays keyed "AFTER" you key it with the switch?
Going from memory here, 110 vdc is what is on that keying circuit.
The keyer switch will have to connect the two leads of this voltage to make the amp key.
When you unkey the amp stays keyed but no Plate current?
I would try another Keyer, or just another rca jack and short it together to see if the amp keys and unkeys.
If it still keys then the keyer switch is eliminated and will move on to other circuits that may or may not be causing the problem.
On your schematic the link i posted at the bottom left you will see
a 120v ac and a BLU this is the keying voltage coming from the transformer.
D 17 rectifies it to a negative DC voltage, just follow that line around to your antenna relay coil. RL1.
This voltage continues down to r16 and then to the antenna relay ( the keying switch.)
I am thinking it may be your keying switch. Or a tube.
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SB200 staying keyed.
Thank You Thank You wavrider I had to replace relay and then I replaced r21 and r22 and she is working fine now. It does not do what my Phantom does but about 500/600w using a 75/80w drive and reports that I am very loud in the DX world I plan on using this mainly with my Siltronix 1011c on sideband. Thanks to this forum and all you great people. Jimbo165
Thank You Thank You wavrider I had to replace relay and then I replaced r21 and r22 and she is working fine now. It does not do what my Phantom does but about 500/600w using a 75/80w drive and reports that I am very loud in the DX world I plan on using this mainly with my Siltronix 1011c on sideband. Thanks to this forum and all you great people. Jimbo165
Glad you got it working.
That old Silkie may have a little to much drive for the SB 200, have to use the mic gain to control the drive. 80 to 85 watts of drive is all it takes for full output.
I like the old silkies too, I have 1011D and two 1011C, now if I can only find a B model.
That old Silkie may have a little to much drive for the SB 200, have to use the mic gain to control the drive. 80 to 85 watts of drive is all it takes for full output.
I like the old silkies too, I have 1011D and two 1011C, now if I can only find a B model.
SB200 stays Keyed
Wavrider I am using Heathkit some now and when running power output up to 400w to 600w range after I unkey the relay still stays on alittle like ssb but just a little longer if I rehit hit keying button unkeys instantly not a big problem but is there a resistor I am overlooking to replace that speeds unkeying it up. Thanks Jimbo
Wavrider I am using Heathkit some now and when running power output up to 400w to 600w range after I unkey the relay still stays on alittle like ssb but just a little longer if I rehit hit keying button unkeys instantly not a big problem but is there a resistor I am overlooking to replace that speeds unkeying it up. Thanks Jimbo
Not sure why it is staying keyed.
The keying circuit is only looking for a ground, I would look at the switch you are using for keying the amp.
You mentioned you did replace the relay. Is it the same type of relay as the original?
SB200 staying keyed
Wavrider I did not have a two contact relay but used a 3 contact dc relay just did not use center contact but I believe I will order one just like old one if I can find it and change it out. Will do same for keying pushbutton. This is a nice amp and I can see why alot like them. I seen wavrider that current going to relay was dc so I did put a dc relay in could not find any info on schematic as to what it was. Is that my mistake the relay? Thanks guys for the replys it is a great help to us. Jimbo165
Wavrider I did not have a two contact relay but used a 3 contact dc relay just did not use center contact but I believe I will order one just like old one if I can find it and change it out. Will do same for keying pushbutton. This is a nice amp and I can see why alot like them. I seen wavrider that current going to relay was dc so I did put a dc relay in could not find any info on schematic as to what it was. Is that my mistake the relay? Thanks guys for the replys it is a great help to us. Jimbo165
The 3PDT relay will work just fine.
You need a 110vdc relay.
Do you use your siltronix on 10 meters?
I use mine there occasionally and have a blast telling the DX ops I am using an old tuber.
They ask OH? is it a Drake or a Collins? Sounds really good audio.
I laugh and reply nope just an old $25.00 flea market special Siltronix 1011D.
It gets so quiet you can hear the static hiss when they find out it is an old silkie.
You need a 110vdc relay.
Do you use your siltronix on 10 meters?
I use mine there occasionally and have a blast telling the DX ops I am using an old tuber.
They ask OH? is it a Drake or a Collins? Sounds really good audio.
I laugh and reply nope just an old $25.00 flea market special Siltronix 1011D.
It gets so quiet you can hear the static hiss when they find out it is an old silkie.
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