Well little did I know the fun actually was NOT 🚫🚭 over

I had pulled C23 as well and checked it ✅✔️

No smoking gun so I put everything back together

Or so I thought


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I plugged it back in turned it on and to my horror the relays were clicking so bad it sounded like a bowl of rice crispies (or Orville Reddenbocker)

So I thought I had plugged something in wrong or left something unplugged but it looked ok
Then I started wondering if I soldered the transistors in backwards.

Well here is a pic with C24 removed

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I had written down on my notes C24 at the top so when I glanced to look for the markings I thought top to bottom = left to right.

Oh well

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Time to do it again....more practice 

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Now it's back to where it is working like before .

 

Oh well I guess I've had my fun for the night



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Anyhow so much for my plan getting voltage readings and stuff.  Because the boards face inward and the only way I can get access to the top of a board is by unplugging everything

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Besides why do that when you can do bonehead stuff like remove components for no reason except that somewhere sometime some guy amongst the entire world 🌎 had that part go bad

Oh well I need some practice anyway.

So I removed Q24

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To be fair i did diode and resistance checks but yeah I guess in circuit they could mean anything.

So while all the cool people in town are partying and getting lit and spending hundreds of dollars on fireworks 🎆 🎇 guess what my excitement is:

Testing this PNP device on my peak atlas.

Oh wait I have a multimeter I'll do that first

 

It occurred to me that when checking transistors in circuit power on I can:

Locate the collector and emitter resistors

Measure voltage drops across each

Look at color codes to determine value of resistors

Divide voltage  ➗ by resistance to obtain a value for current

Compare Ic to Ie

Pause to reflect on discoveries

Attempt to draw a conclusion(s)

 

Thank you sir it's nice to know heavy hitters like you and Mr DMeek don't take this lightly.

Btw I found this on the interwebz

https://www.eevblog.com/forum/repair/topward-6303a-repair/msg5382143/#msg5382143

I know it's ill advised to start shotgunning parts but I ordered some 2sa1015 anyway and I'm thinking about shooting on sight. 

I already have a bunch of 1815s.

And I already replaced an 1815....and surprise surprise it didn't fix it 

Yes sir thanks I did remove the cover power on and do some rapping on the relays and moving the boards around a little to no avail. 

But I did discover something.....

The slave voltage has full range in parallel mode 

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And stops at about ten volts in independent and series mode

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I appreciate your help I know this is pretty complicated 

It's velly intresting 

Thank you sir I will definitely give that a try this evening   

Ok sorry they are C22 and C23 and polarity is marked (duh) 

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Thank you sir 

I did open it up and take a few measurements per your suggestions

I get about (plus or minus) DC readings

Left side
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Right side I think it said C28 before I flipped the board over

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Repeating in ac volts not much

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But idk about the AC volts because this is with the probes not connected to anything 

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I have a scope and I like to use it but not sure where to probe and maybe these measurements are enough to draw a conclusion...idk.

Seems from the DC measurements the caps are functioning 

In summary the left side won't get past about thirteen volts
But the other day it started working and working really good. Relays clicking like gangbusters    As in I turned it to almost thirty volts and it held steady. 


Then it went back to messing up again 

Do you think it worthwhile to replace these capacitors

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However seems kind of pointless to ask I know this is not proper form to blindly start replacing stuff.

And to be fair up to this point I was like "dude it's a bad relay"

  

Tested by the atlas

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So I was doing an experiment per textbook

Take a 2n3904 ground the base
Put +12 at the collector resistor
Put -12 at the emitter resistor

Ok that in itself was quite a task but I managed and no matter what kept getting a Ve of -3.7v

It took me a while to figure that if base was at ground then thats probably not correct.

So I reconnected configurations ad nauseum and kept getting the same thing 

Meanwhile kept checking that VB = ground.

Finally I was like well hell why don't you check the transistor so I did a diode check with my multimeter and + on base to emitter was showing a one.   

So I grabbed a new one and it showed about 0.67 

Ve with new one in circuit

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Ve with old one in circuit

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And the diagram

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Now the "old" transistor is pretty new from mouser a year or two ago but..to be fair is has been subjected to some abuse like reverse biasing and stuff....

Anyhow I thought I was going crazy 

Also I checked the coil like Mr Jaun said and it seems to match a data sheet I found



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What's weird about the data sheet is I downloaded two pages and I can access and read them etc plain as day but if I try to upload them here they get dim and won't let me do it 

Yes sir thanks definitely better doing it that way if I connect it at voltage I get a click

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If I adjust the power supply "com" and "NC" open at about 16v DC then I have to roll it back to about 6v DC before it closes back up

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Also if I hold the relay while doing that if I don't hear it I can feel it

Well I tested one of these new relays with a power supply and some leads and a multimeter monitoring continuity.

They seemed to open and close fair enough but I'll be damned if I heard a single click 

Idk maybe it's not supposed to make an audible click

But...I think that's what I am hearing click in the power supply as voltage is increased.

Comparing the markings on the devices I definitely see a difference but idk if that means anything.

Oh well it's not like I spent a fortune 🔮 on these.