What Is Probably Wrong With This Circuit?

Thread Starter

abrogard

Joined Dec 20, 2018
77
I'd like your, list, Joe, if that's the way you went that'd be the way to go is how I look at it.. :)

Going to be a slow job though, I'm slow at picking up new software (or anything else)
 

JoeJester

Joined Apr 26, 2005
4,390
I looked at the foil side picture that you submitted a couple of posts ago. On TR4 you have what is labeled as the E and tracing the foil, it goes to the collector. That is incorrect. TR4 C is tied to TR6 C on the schematic. Also TR6 you have the E and B reversed. Look at the pin positions, they are closer to one screw hole than the other.

2sc1030.jpg TO-39-metal-can-package.jpg

When your installing the components and measuring them from the underside, you can compare what connects to the leads to help you out.

Here's what I used ....

substitutes.jpg
 
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Thread Starter

abrogard

Joined Dec 20, 2018
77
News flash:

I think it is fixed. Well I just hammered away at it for half an hour and it didn't blow up or anything.

I found out yesterday but said nothing until now because I doubted it. But I thought I'd give it a test without the input plug as someone suggested and after doing that I thought might as well test it with it.. what's the difference?

So I did and it didn't fail. All that with no serial lamp of course.

So if it is fixed I wonder what it was? I'm thinking maybe the serious cleaning I did around the power transistors TR6 and TR7 on their heatsink there. That was all pretty grotty.

If it's fixed that's wonderful and I'm very grateful for all the help and attention I got. Gave me heart to continue with the thing where it was that far from going to the dump.

For future reference I still wonder about putting in a more modern amplifier to replace that old one - is that a feasible operation or not?

And I will be going ahead with learning Tina-Ti and I'll try some practical work, building simple circuits, albeit without quite the sense of urgency I guess.

Thanks again to all. Made this bunny feel a little smarter. :)

p.s. might finally come to grips with that raspberry pi I bought years ago and never even unwrapped. I've no doubt that could fit into a circuit here or there to make something interesting?
 

Thread Starter

abrogard

Joined Dec 20, 2018
77
Excellent. I've put HTTrack on the job, we'll see how it goes. :)

hmmm. it did no good. have to do it manually, one by one... fair enough... :)
 
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JoeJester

Joined Apr 26, 2005
4,390
The only thing that still concerns me is the 32 volt supplies being closer to 24 volts. But if your happy, that's all that matters.

You might want to check the two electrolytic after your tester arrives. If the ESR is too high, you can order them at your convenience.
 

Thread Starter

abrogard

Joined Dec 20, 2018
77
I will do that, Joe. I think the volume is somewhat low, especially the 'beat' volume but I don't know if that's how it was designed. It could perhaps be because of this low voltage?

And that voltage was measured with the serial lamp. There'd have to be some voltage drop there wouldn't there? Would that effect the final working voltage on the 32 volt rails ( if it is right to call them 'rails' ) ?
 

JoeJester

Joined Apr 26, 2005
4,390
And that voltage was measured with the serial lamp. There'd have to be some voltage drop there wouldn't there? Would that effect the final working voltage on the 32 volt rails ( if it is right to call them 'rails' ) ?
That is a reasonable assumption. Print out a copy of that schematic and write on it the voltages you find. Then file it for future reference.
 

Thread Starter

abrogard

Joined Dec 20, 2018
77
That's a good idea. But I don't feel like taking the thing out again. I'll write the voltages I found with the serial lamp in place and as for the 'real' voltages perhaps I'll get a line on them from the simulation circuit if I get it going...
 
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JoeJester

Joined Apr 26, 2005
4,390
If your going to continue this type of work, you will need an oscilloscope. A frequency counter would help with the individual key frequencies.

So, think about what you intend to work on, the frequencies involved and then you can find the new toys you that will help you with those projects. You might be giving yourself some presents at various times during the year.
 

Thread Starter

abrogard

Joined Dec 20, 2018
77
If your going to continue this type of work, you will need an oscilloscope. A frequency counter would help with the individual key frequencies.

So, think about what you intend to work on, the frequencies involved and then you can find the new toys you that will help you with those projects. You might be giving yourself some presents at various times during the year.
Yep. Sounds good. I always seem to need an audio amplifier so I think I'd like to build some of them. In the past I've had that same plan and have even sent away and got the parts from a part list for a project - and never built it and now have bunches of parts I don't know what they're for !

Like to do it for real, finally.

And NVR's. I'd like to build my own NVR. Mine annoys me. It's mainly a software thing is the problem but I can't change the software on it. If I make my own I can put what I like on it. A raspberry PI might be just the thing for that.

I've got this el cheapo DSO coming. I don't know how useful that will be. And a frequency counter? O.K. I'll look into that.

Thanks for your help, Joe. It was good. :)

p.s. was just googling frequency meters. I suppose audio range might be what I'd require in the future if I'm going to build amps. But maybe I should build my own meter first might be a good way to start? There seem to be a lot of kits around.
 
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Thread Starter

abrogard

Joined Dec 20, 2018
77
No It's not the same And something has gone wrong. When I go to view the order I see a message from ebay about having to remove the listing and the seller no longer being part of ebay etc...

And when I look at my order record it occurred to me that maybe I've bought only a shell to put a circuit board inside? Even if it does turn up.

Even if I've been ripped off it doesn't much matter. For $9.

I'm interested ot know of any 'reviews' or accounts of experiences with these things...

ebayelectronictihng.png

hmmm I googled a bit and it seems the dso150 is a kit - as you probably already know - and they sell shells for them and there's bodgie sellers around. It looks to me like my sale was truly advertised as the kit + shell but I imagine I'll only get one or the other when the order turns up. IF it turns up.

That'd put me in the market for something else. Keen to receive suggestions. :)
 
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Thread Starter

abrogard

Joined Dec 20, 2018
77
Yes, I see that, Joe. I don't know why but I was thinking you were in Aus. Not so? I should have know from the NEET I suppose.

The organ is still working fine. Any thoughts on the practicality of putting a new (better?) amplifier in it?
 

JoeJester

Joined Apr 26, 2005
4,390
Well, my location is listed and we usually recommend that so we have a clearer idea the supply chain.

You could put a power amplifier in place of the one you just tested. Why do you want to replace the amplifier? All the parts have replacement components. But if you want to go down that path, it can be done as you will need to identify the input to the pre-amp that supplies the installed power amplifiers.

You could write down the pros and cons of installing a new amplifier.
 

Thread Starter

abrogard

Joined Dec 20, 2018
77
I don't want to, Joe. I just wondered. Back then when I was working on it. I thought one day how about I can't fix it? I wonder if I could put something else in it?

Big thing you know, not to waste that enormous organ, lovely old piece of furniture?

I can't write down the pros and cons though, Joe. Because I don't know them.

If it was irredeemably broke (the amp only) I'd say the pro would be I'd get the thing going again.

Cons I'd guess at. Maybe too big a hassle and too expensive? I suppose we can find what inputs it has to handle? Not too much of a problem? Circuit guys like yourselves could figure that out from the circuit diagrams maybe? Well then how much of a problem is it finding an 'off the shelf' amp that will handle those inputs?
And with an output that won't blow the speakers on the one hand and won't be too small to drive them on the other?

I've no idea.

That's why I asked I guess. General knowledge.

And talking about knowledge. I have my ESR Tester and I don't know how to use it. It comes with no instructions whatever.

I found an AliExpress page that sells precisely the same instrument but I can't understand what it is talking about.

Here it is:

https://www.aliexpress.com/item/Fre...istance-Meter-Test-In-Circuit/2032765626.html
 

JoeJester

Joined Apr 26, 2005
4,390
If that is your ESR meter, the chart on the meter gives you an idea of the maximum reading for the various capacitors.

Here is a chart from the Sencor LC 77 technical manual. That equipment used one frequency to test capacitors, unlike yours, but the info may provide some insight.

ESR-CHART-FROM-Sencore-LC77-manual.jpg
 
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