Completely Out of My Depth - Modulus 50w 69 Build

[BlueX]

When you're done with the inputs: There seems to be something between p8 and p9 on V1. In the pic it looks like a wire strand.

You could go over and clean the octals (V4/5) also. Seems to be some residue left.

 

[NickKUK]

You may want to ensure there's good clearage circled:


Any wiggling of tubes etc are likely to cause a short.

Edit- this is especially important as the choke attaches to that leg of the screen resistor. Which means it has almost full B+ on it

 

[kingfredward]

Thanks everyone for your help

Does anyone know where the black wire would go in this instance?

with the updated wiring like this

So the wire on the wire on the first turrent would go where in this?

Would it just wire straight to ground?

 

[PelliX]

Would it just wire straight to ground?

Uh, yes, those black arrows in the second image and the black wires depicted in the first image are ground, yes.

 

[kingfredward]

Great shall I wire it straight to the chassis ground lug or ground on the speaker jack by the bottom right corner of the resistor

 

[PelliX]

Let's go with the chassis ground lug for now. If need be it can always be moved later.

I was sort of off and on looking in to this thread, doing other stuff most of today; did you give it a general cleanup (valve sockets, solder splatters/debris)? Have the presence of bias and HT voltage been established?

 

[Marcomel79]

Also check this resistor, it looks like youve burned it with your soldering iron. Check its value and its connection to ground. Do the same for V4.

 

[Marcomel79]

Have the presence of bias and HT voltage been established?

Also this ^^^^

 

[Marcomel79]

In post #118 you state you didnt get a reading off your 1ohm resistor. If on standby you wont get a reading. Check it again for both tubes OFF standby

 

[kingfredward]

Good afternoon all.

I am back from my business trip so I have finally been able to sort the inputs. I did it as per the new schematic that you all suggested.

I started it up and nothing went bang which is good. I did establish HT voltage which was a stable 320v

However no luck on establishing any reading of that 1ohm resistor. I tested it on its own and I had a reading. With power I am unable to get connectiong. The way I am doing is by having ground to the chasis and the prop on the corner of the 1ohm resistor is that the correct procedure?

Further I tested all the inputs and I didnt get any sound on any of them

Also cleaned up in the inside and got rid of any strand or debris.

Think I may just take it to a tech by this point what do you reckon?

In post #118 you state you didnt get a reading off your 1ohm resistor. If on standby you wont get a reading. Check it again for both tubes OFF standby

 

[PelliX]

However no luck on establishing any reading of that 1ohm resistor. I tested it on its own and I had a reading. With power I am unable to get connectiong. The way I am doing is by having ground to the chasis and the prop on the corner of the 1ohm resistor is that the correct procedure?

Procedure is correct, but what do you mean by "unable to get connection"? What kind of reading did you get without the valves in?

Also cleaned up in the inside and got rid of any strand or debris.

Noice!

Think I may just take it to a tech by this point what do you reckon?

Seems you're awfully close to the finish line to go into the pitlane, but that's just my opinion...

 

[kingfredward]

Procedure is correct, but what do you mean by "unable to get connection"? What kind of reading did you get without the valves in?



Noice!



Seems you're awfully close to the finish line to go into the pitlane, but that's just my opinion...

haha your right I should keep going.

So I get no DC reading at all I get AC voltage reading oddly enough. Around 25v Any clue?

Thanks

 

[PelliX]

So I get no DC reading at all I get AC voltage reading oddly enough. Around 25v Any clue?

So you're saying that you measure around 25VAC without valves in, and with the valves in zero volts? In that case you want to keep the valves out and take a gooood look at your bias supply. Pics appreciated.

 

[kingfredward]

Woops I seem to have blown a fuse when I accidently created a spark with my multimeter so going to have to wait now.

 

[PelliX]

Woops I seem to have blown a fuse when I accidently created a spark with my multimeter so going to have to wait now.

Ouch. Which fuse did you pop, plug, amp mains, HT or the one in the meter itself?

 

[kingfredward]

Ouch. Which fuse did you pop, plug, amp mains, HT or the one in the meter itself?

i blew HT fuse when I caused a spark across the b+ wire lol shaky hands

 

[PelliX]

i blew HT fuse when I caused a spark across the b+ wire lol shaky hands

Could be worse, but be careful indeed. Hopefully the fuse did its job and saved the other bits. Sometimes a croc clip or two can be handy for places where there's no room for "shaking". You can get relatively cheap sets of probes that include clips you can use for this stuff, too. Also consider probes that are shielded right up to the tip. No shame in working with the tools that work best for you.

 

[Marcomel79]

When trying to get a reading through the 1ohm resistor, clip one probe to the chassis, and one to pin8. If you clip it to pin1 you wont get a reading. Also check your ht OFF of standby