Valiant Bandswitch

[W7SOE]

I am working on a "new to me" Valiant.  When I turn the band switch clockwise it will hit a stop.  I installed the knob there, pointing at the 11m band.  But if I turn it counter clockwise it will continue past 160m four places!

What is going on?  Is my setup missing a stop on the other end?

Thank you

Rich
W7SOE

[KA2DZT]

What happened to 10 meters??  May be a few positions for 10 meters.  I guess the "11 band" is 11 meters.

Fred

[W7SOE]

Yes, 11 meters.

The band switch engages that funny cam-block assembly that turns a wafer switch in the VFO.  This happens, as I have the knob configured, when I switch from 11m to 10m , and from 80m to 40m.  I have no idea if this is correct.  And the switch continues past 160m.....

When the cam block turns the switch there is arcing noises from the VFO and a burning smell so there are obviously more issues!  

I am hoping you Valiant experts can give me some insight into all of this.

thanks

Rich

[WQ9E]

Rich,

The switch should mechanically stop at the 160 and 11 meter extremes.  I believe that this is done through the regular switch detent assembly but the cam actuator may come into play.  It has been awhile since I have had to set up the cam section.  But a look underneath should make it clear. 

The VFO operates on 1.75-2.00 Mhz. when the Valiant is on 160 and 80 and then switches to 40 meter output when operating on the other bands except for 11 where the VFO frequency is again shifted.  So the cam switch is activated when moving between 80 and 40 and again when moving between 11 and 10.   So your cam setup is close but with the arcing/smoke it may not be moving cleanly between selections with the vfo switch.  The assembly manual (available from Bama) covers cam indexing.

If you haven't been inside the VFO at the least you need to check that the VR tube current limiting resistor has been increased in wattage.

I put together a page of notes from working on a number of Valiant transmitters, PM me if you want a copy.  There are a bunch of user induced issues possible in the Valiant including destroying the VFO coupler, destroyed LV transformer if early 866A filamentary cathode wiring isn't upgraded, flashover from MV rectifiers if they are treated properly during servicing, etc.

[W4AMV]

Rodger, is the cam switch operation in the Ranger the same as the Valiant? That is between what bands does the index tab on the band switch engage the cam? I have a similar issue with the Ranger as the band switch is a bit frozen, need cleaned and lubricated and the switch-knob  is now misaligned.

Thanks, Alan   

[WQ9E]

Alan,

It is the same for the Ranger.  160 meter VFO output for 160 and 80, switches to 40 meter output for 40 through 10 meters. 

[W7SOE]

The wafer switch (SW1) in the VFO is indeed zorching, ugh.  

I see that the switch section on pins 7 and 8 have 300V on it via pin 8.  I think pin 6 has close to ground potential via L3, L19, and SW2.  I think......   Staring at these switches in the schematic gives me a headache....  

I have attached a picture.  The wire attached to pin 6 (I think) is going up in smoke as the switch rotates.  It only seems to do this in an "intermediary" position.  Once all the way switched, no smoke.  

I have looked at the construction manual and the cam block assembly "seems" to be aligned.  That said, I may loosen D1 and D2 and realign according to the manual.

Still can't figure out why there is no CCW stop on this switch.....

Rich

[k7iou]

Are the 2 contacts touching the nut???

[W7SOE]

Are the 2 contacts touching the nut???

No they are not touching.

I have removed the wire from pin 7.  (The yellow wire in the picture)  It still zorches.  It is the contact of pin seven, that shorts the two contacts as the switch turns.  As it is drawn in the schematic  it is shorting the contact that is positioned over pins 7 and 8 with the contact that is shown between pins 4, 5, and 6.  I hope that makes sense....

The contact shown across pins 7 and 8 has 300V on it from pin 8 via R5.

The contact shown between 4, 5, and 6 is at ground potential via L3, L19, and SW2.  So when the contact at pin 7 shorts them as it turns, zorch...

This is starting to drive me nuts.  What am I missing?  Should that contact short the other two contacts as it turns?  Am I reading the schematic right? 

I removed mods that allow a Heathkit ssb adapter to be used, could that have created this problem?  I check and those mods seemed unrelated.

If this is something stupid (It usually is) I am ready to find it now!

Thanks

Rich

[KA2DZT]

Are the 2 contacts touching the nut???

No they are not touching.

I have removed the wire from pin 7.  (The yellow wire in the picture)  It still zorches.  It is the contact of pin seven, that shorts the two contacts as the switch turns.  As it is drawn in the schematic  it is shorting the contact that is positioned over pins 7 and 8 with the contact that is shown between pins 4, 5, and 6.  I hope that makes sense....

The contact shown across pins 7 and 8 has 300V on it from pin 8 via R5.

The contact shown between 4, 5, and 6 is at ground potential via L3, L19, and SW2.  So when the contact at pin 7 shorts them as it turns, zorch...

This is starting to drive me nuts.  What am I missing?  Should that contact short the other two contacts as it turns?  Am I reading the schematic right? 

I removed mods that allow a Heathkit ssb adapter to be used, could that have created this problem?  I check and those mods seemed unrelated.

If this is something stupid (It usually is) I am ready to find it now!

Thanks

Rich

Rotary switches are made two ways,  make before break and break before make.  The stops on the switches are usually between the front metal plate and the spring.  Many different methods used for stops, you'll have to look close to see whats wrong with the stops.

Fred

[W7SOE]

Rotary switches are made two ways,  make before break and break before make.  The stops on the switches are usually between the front metal plate and the spring.  Many different methods used for stops, you'll have to look close to see whats wrong with the stops.

Fred

Thank you Fred.  That contact seems to perfectly bridge the two as it turns, like it is make before break, but that is a short!.. Ugh.

Rich

[N2DTS]

Maybe someone replaced the switch with a non standard one?
That would explain the lack of stops and the shorting/non shorting problem....

[W7SOE]

The lack of stops is on the bandswitch, this one is SW1 in the VFO, driven by the cam block.  Maybe the issues are related...............

Rich

[ka4koe]

I finally received a replacement for my band switch and will be installing it ASAIGATI. That assembly is really a hateful thing.