Shunt regulator test failed

[arisrock]

Hi,

This is my 4th kit build, but the first AC kit. The others were battery powered to build skills.
I have build the kit so far with good readings, unto the shunt regulator when things got sketchy.
I would very much appreciate any help on what might be wrong with the build, or indeed my measurements,

(1) I am not sure if I am testing the right terminals. Included photo 2214 to confirm
(2) The readings I'm getting from this are around 0.05VDC. So I'm guessing something's wrong.
(3) Readings from the power supply are 289VDC (a little high)?
(4) Tube is lit. (all tubes were lit).
(5) I've included a bunch of photos of the Shunt regulator build to ask if there's anything obviously wrong...

thank you in advance for your help and let me know if you need anything else to help me diagnose the problem

 

[Jay]

is your multimeter set for AC, or DC for the power supply reading?

 

[arisrock]

Using a Fluke 117 in DC mode.

 

[Deke609]

I'm just a novice, so I can't provide any expert advice. But it's still very early on the U.S. west coast, so it may be a couple of hours before PB checks in. In the meantime, there are a couple of easy things to check:

What VDC reading do you get at IA and at IB? This should tell you whether it is a problem on the board or before the board.

Assuming that checks out (I don;t have an Eros, so I don't know what value you should have here), I'd double check that the black bodied 431 regulators and the PN#### transistors are in the correct spots - they're easy to mix up.

cheers, Derek

 

[Paul Birkeland]

1.  You need a proper set of side cutters.  Everything installed on that board has leads that are way too long poking out.  They need to be trimmed back so your board looks exactly like what's in the manual.

2.  You need to be a bit more mindful of the manual when it says "stripe 1/4" of jacket off the wire".  I see many wires with way too much jacket stripped off.  If two of those bare portions of wire touch each other, or a portion of bare wire touches something random on the board, you will have a new problem to diagnose.

3.  Your solder joints all need to be reflowed, with more heat if possible.  This is more than likely the culprit for why nothing is working on that board.  If you have an adjustable soldering iron, tun it up all the way.  If your iron isn't adjustable, be sure it's rated for 45W.  Also be sure you are not using lead free solder.  If you have met all those criteria, then you need to hold the iron on your joints until the solder liquefies and flows through to the other side. 

 

[arisrock]

Thank you all for your help and advice.

I am using a temperature controlled solder iron at 400F. I'm now reading most folks recommend 500F and upwards. I admit I am a little frugal on the soldering quantities I apply as well. I'll re-solder the joints and see what happens.

Will get some flush clippers too and follow the rest of your tips.

thanks again!

[CORRECTION: Sorry I sent everyone soldering mad with this mistake, but, I actually had it to 400C (not F) which is 750F. Still, I appreciate all the soldering advice!]

 

[Doc B]

400F is waaay too low. Use 650F - 700F.

 

[Thermioniclife]

Hello, I run my iron at 650 deg. F for most everything through hole and point to point. I use 60/40 or 63/37 tin/lead solder.
My main tip size is 0.62" but an .032 is useful for small through hole components and I use a large 1/4" tip for soldering heavily loaded terminal strips or other large heat soaking requirements.
I've assembled thousands of PCB's over the years and this is the culmination of my experience. in my opinion you should use a tip size that allows the joint to heat thoroughly without getting cold in the process.
I do not have an Eros (yet) but I can see that the large ground lug that your turntables ground connects to is going to need a ton of heat so I think I would cut all the wires that connect to that ring terminal to length and remove the bolt from the chassis, insert all the leads and perhaps crimp the barrel to hold them and using the biggest tip you have solder it. if you leave that ring bolted to the chassis plate while soldering will be an exercise in frustration as the plate will soak much of the heat from the joint.
wishing you well, safe and enjoy.
Just my 2 cents worth.

 

[Paul Birkeland]

ALL THE WAY UP!!!!!

 

[Doc B]

Well, yeah, that's what I have been doing for 30 years, and what my Elmers did. But you have to ease these newbs into it. I still haven't gotten over a tech using my Hexacon TOT iron as a pry bar and snapping it in half about 8 years ago. I loved that old iron. Really fast, ran at 800 all day. Replacement price was nuts so the work lab got a Hakko 936 and I bought a used Ersa 2000 to use at home. The Ersa is pretty fast too.

 

[Thermioniclife]

Hey Doc, I used a hexicon with a red wooden handle and a tip that could hold a ton of heat to solder 8awg crimped barrel connectors in the past I called her Big Bertha. Holy smokes she had a lot of A** behind her. loved that iron. I think it may be important to point out that having to much heat can drive the solder away from the joint instead of drawing it in. i'm not an electronic engineer by any means but I kinda have had a lot of experience in soldering.

 

[Doc B]

I find that the high tip temp - for an experienced tech - means a short dwell time on the joint. That seems to mean less collateral damage to the wire jackets and other sensitive stuff. It's counter-intuitive, but like a lot of production skills it's something that looks impossible (e.g., twisting preztels, that one took me a while) but isn't once you get the feel for it.

By the way, don't watch most of the preztel twisting videos on youtube, they are done by poseurs. These guys do it like production workers -

https://youtu.be/Yi0udzUqTOY

 

[grufti]

I couldn't agree more with high tip temp soldering. I sort of drifted into it, because there isn't much soldering advice out there that says: 800F is a really good temperature for just about anything. My first high temperature adventures were mostly accidental and then I noticed that, hey, this works really well and it's quick. Now I tend to believe that it also reduces the heat exposure of the parts and of the pcb. Again, your mileage may vary and you need to be quick, meaning that your parts need to be in place and your solder ready.

 

[Deke609]

Same with me. 800F is my default temp setting, but I'll drop to 700 for tiny pcb work and go to max for heavier duty stuff like solder tabs bolted to the chassis.

And as Doc B noted, the key is short dwell time: heat the joint area super fast and add solder.  For me, that means deciding exactly where and at what angle I will place the tip and the solder wire, and getting "into position", before making contact. Sometimes that requires a bit of thinking - e.g., for hard to reach spots, or joints with multiple wires that will require multiple contacts with the soldering tip. A tricky solder joint can take me a few or more seconds to plan, but then only 1-2 second to do.  I find that crimping wires to make a solid mechanical connection really helps too -- those lower lug round holes can be a bit challenging crimp-wise.

cheers, Derek

 

[arisrock]

Hey everyone. still no luck

(1) I re-soldered everything that didn't look soldered well.
(2) I clipped everything tight with a new tool.
(3) I found a wire that wasn't soldered (and seemed connected) from 29L to D6
(4) All 4 LED's light up, as they did before.
(5) Still not reading meaningful. Volts at the MJE terminals.

Any more recommendations? I must have done something wrong with the board or the wiring but I just can't see it.

 

[Paul Birkeland]

Can you post some fresh photos? 

 

[arisrock]

SOLVED.. Ok, so this is the dummest. But.. It seems I was measuring the wrong thing, Instead of putting the "-" Voltometer terminal at the Ground of Eros, I put it at 31U instead, and measured 217V at the terminals, as it should measure. So everything was working all along, but I was measuring the wrong thing....

 

[Paul Birkeland]

Well, you have done a lot of inspection on your work and you can have some additional confidence that all is well ^_^.