The Much Anticipated (?) Bluesmaster Build Thread

[martin manning]

That says that the 150R from 2 isn't connected to ground.

[Raoul Duke]

Measuring across the two heater leads coming out of the transformer with the bulb limiter in place gives me 6.4vac.

IMG_0218.jpeg

[Raoul Duke]

That says that the 150R from 2 isn't connected to ground.

I’ve actually got that resistor on pin 2 of V4. Should I move it or connect the heater bridge and see if the voltage balances out?

[martin manning]

Do you have heater leads connected between the two sockets? If not that would explain it. I thought I saw a back/white twisted pair.

[Raoul Duke]

Do you have heater leads connected between the two sockets? If not that would explain it. I thought I saw a back/white twisted pair.

I added the twisted pair late last night to perform sluckey’s test; but they weren’t soldered in to V4. I was measuring from the loose leads. I took them out a little while ago to basically strip back the pins and check everything methodically, piece-by-piece and start over in case I missed something small.

Makes sense - the second ground reference wasn’t in the circuit - so it compensated by pushing all the voltage to one (grounded) side. Do I understand that correctly?

[martin manning]

Makes sense - the second ground reference wasn’t in the circuit - so it compensated by pushing all the voltage to one (grounded) side. Do I understand that correctly?

That's it. I seem to recall the same question coming up in your 102 build.

[Raoul Duke]

I’ll have to look and see. If so - shame on me for forgetting that lesson.

I can still remember the serial number of every weapon that was ever assigned to me (going back ~30 years now), but I can’t remember what I ate for dinner 3 days ago. Age, TBIs, too much Laphroaig, all of the above?

Onward to the PI and completion of the power section

Thanks Martin!

[Raoul Duke]

Sorry for the filament string wild goose chase. I missed you saying you had correct voltage between the filament pins.

No worries! I appreciate any feedback and any opportunity to learn. It’s all very good

[martin manning]

Yea, sorry for the diversion. If you went ahead and wired the rest of it up you'd have been fine. Hopefully the learning was worth the trip!

[Raoul Duke]

Yea, sorry for the diversion. If you went ahead and wired the rest of it up you'd have been fine. Hopefully the learning was worth the trip!

Always worth it Martin; and appreciated

[Raoul Duke]

Been playing “Operation” with the main board for the last couple hours and I’m getting close to being at the next test point.

I was hoping to get some feedback on the PI lead dress if possible before I nail it. Took a gander at the Livesey site and the documented Bluesmaster builds here - most notably Ian’s (thanks Ian!) - in order to try and get it right the first time.

My concern is the wad of OT secondaries in close proximity to the pin 1 wire. Any critiques, suggestions etc. are appreciated!

IMG_0220.jpeg

[Raoul Duke]

Power amp check complete - the power amp is fully operational.

B+1: 477
V5 plate: 472 biases at 38mvDc
V4 plate: 472 biased at 40mvDc

Bias pot sits a little past noon - right in the middle

V3a plate: 297
V3b plate: 294
V3 cathode: 44

Not hearing any weird noise from the PI or OT, so I guess V3b plate wire is ok where it is for now?

Plugged in my footswitch to test it and nothing is lighting up. Switches and DIN are working correctly (12v in pedal and 0v in manual) and the pedal works with my 102. Relay boards have 12v at the coil and ground continuity at the eyelets specified in the board plans. Strange.

I have to track this down before I get too much further, space to work around the relays is tight and the main board connections and HRM board make it really tight…

Still a good day though

[martin manning]

Not hearing any weird noise from the PI or OT, so I guess V3b plate wire is ok where it is for now?

Do you mean the OT primary connections/NFB?

[Raoul Duke]

I guess that makes more sense thinking about it.

Re-checked my relay wiring at the din and switches back to the negative side of the coil and everything seems right. The runs from the relay PS board to the switches/DIN seem correct, as does the regulator side - 12v to both relays. I’m using the same Omron G5V-2 I used in my last build.

Am I testing the FS too early? I figured with 12v headed to the switches I’d be able to. I feel like I’m missing something obvious.

[Raoul Duke]

Yep, obvious.

The DIN plug needed a ground reference to actually work, lol. Ran the wire back to ground 5 (as it’s labeled in the layout) and the FS magically works now.

Getting good at catching my own f-ups; now if I could get a little better at not making them…