Stage Line 500W amp repair project

[WHONOES]

They look OK. Just need to get a breakout box made up.
You will need two of these as well plus a small box to mount them in such as the ones below. A small rubber grommet should also be used to protect the incoming lead from your sound card.

BNC Chassis Panel Mount Insulated Female Socket Solder Connector | eBay

New Electronic Project Diecast Aluminium Enclosure Box 1590/1032 Series UK | eBay

Edit: Almost forgot, some BNC to Croc Clip leads will also be very useful. See below.

BNC to twin croc clips test lead suit frequency counter CB ham amateur radio etc | eBay

 

[WHONOES]

Because the input impedance of your sound card is a bit of an unknown, it could affect the calibration of the scope leads. Sig Gen inputs are normally 1MΩ switchable to 50Ω. I expect the I/P of your sound card is somewhat less than that. You may need to buffer the Scope leads. It's not difficult.. I'll come back to you on that.

 

[bikemech]

They look OK. Just need to get a breakout box made up.
You will need two of these as well plus a small box to mount them in such as the ones below. A small rubber grommet should also be used to protect the incoming lead from your sound card.

BNC Chassis Panel Mount Insulated Female Socket Solder Connector | eBay

New Electronic Project Diecast Aluminium Enclosure Box 1590/1032 Series UK | eBay

Edit: Almost forgot, some BNC to Croc Clip leads will also be very useful. See below.

BNC to twin croc clips test lead suit frequency counter CB ham amateur radio etc | eBay

Does the box need to be aluminium?
Is it for shielding purposes?

 

[WHONOES]

Yes to both. Don't buy anything yet.

 

[WHONOES]

See attached schematic for your scope probe conditioning circuit. It will run from a single 9V battery. Read the notes carefully.
You should build it up one a piece of Veroboard and put it in your Ali' box with a switch to turn it on and off.

 

[bikemech]

See attached schematic for your scope probe conditioning circuit. It will run from a single 9V battery. Read the notes carefully.
You should build it up one a piece of Veroboard and put it in your Ali' box with a switch to turn it on and off.

Ok, think i have a strip of Veroboard, this is going to be a little challenge in itself

 

[WHONOES]

It wil be good practice. Have you read and understood the notes?

 

[bikemech]

It wil be good practice. Have you read and understood the notes?

I am just about to pri t it out and study it, if i am unsure of anything i will ask on here,

Cheers

 

[bikemech]

Ok, so C1 and C2 are non polarised? ,X3 is the output, why is X4 there if it does nothing ?

 

[bikemech]

Will this piece of board be wide enough ?

 

[bikemech]

Also what are the TL034-101, look like IC on google search

 

[bertus]

Hello,

C1 can be non-polarized.
C2 can be polorized.
They are decoupling capacitors.
This thread on AAC will tell you more about those capacitors:
Decoupling or Bypass Capacitors, Why?

Have a look here for the TL034
https://www.ti.com/product/TL034

Bertus

 

[bikemech]

These ?

https://www.ebay.co.uk/itm/3-x-TL03...-/324355676159?_trksid=p2349624.m46890.l49292

 

[bertus]

Hello,

Farnell states that the chip given on ebay (TL034IN) is obsolete.
This is the TL034CN at Farnell:
https://uk.farnell.com/texas-instru...L034CN&searchref=searchlookahead&exaMfpn=true
But that had a large lead time.
The dual version TL032 is direct available:
https://uk.farnell.com/texas-instruments/tl032cp/ic-op-amp-dual-jfet-dip8/dp/3005098?st=tl032

Bertus

 

[WHONOES]

The ones on ebay are very expensive. You could use a TL074 instead which is available from RS components. You could also get the rest of your bits from them as well.
I originally chose the TL034 as its O/P goes from rail to rail but on reflection that is probably not necessary.

The only reason for X4 being on the diagram is because you get 4 to a pack. The 4th one is not needed but you cannot leave just flapping about otherwise it will probably oscillate or some really strange this that you do not want.

The supply bypass cap' does not need to be bipolar, that is just a quirk of the sim' package that I use.
It makes nice schematics which is why I use it.

Edit: Just seen the TL034 that Bertus pointed out on Farnell. You can use that and also get the rest of you bits from there.

I meant to add on the notes that you should include a small rotary switch in your box so that you can change R1 to become 1MΩ, 100KΩ. 10KΩ and 1KΩ.
This will then give you division ratios of 1:1, 10:1, 100:1 and 1000:1, which along with your scope leads should cover most eventualities.

 

[bikemech]

Would that be a 4 position rotary switch ?
And does it matter if the resistors are wire wound or film ?

 

[WHONOES]

4 pole rotary is fine. You can get relatively cheap ones with 12 ways with a stopper that you can use to set it to any number that you choose.
Not wire wound resistors, they will be inductive. Not at all what you want. Metal film is fine.

 

[bikemech]

Is it me or is C1 and C2 the same just marked up different ?

 

[bikemech]

Is it me or is C1 and C2 the same just marked up different ?

maby not

 

[bikemech]

Is the voltave important with these caps, smallest i can find is 63v