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Anyone near Rotherham who could test my Scope?

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Scope Update

Hi Eric,

Sterling job you did there, sorting out the 3046's - Thanks.

Yes I do intend to buy some, Rapid are having a one day sale from noon tuesday to noon wednesday, check it out!

I am ordering quite few ICs from the scope, just in case, the only ones they don't have are the LM733CN differential amps!

Just wondered if there was a substitute that could be used that you knew of?

I tried googling for a sub but got nothing and only DigChip seem to have any!

Anyway thanks for the help so far and I'll let you know how it goes when the parts arrive!

Also if there is anything you need from Rapid while I am ordering let me know, it would be a pleasure to get them for you, as I am in your debt for the meter still, not to mention the help you have always provided :)

Thanks again Eric............Al
 
hi Al,

Ref the E421 its a dual jfet 50V 50mA n-chan

Look at the attached doc, managed to get some info...
 

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  • al1.doc
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Hi Eric,

I also have been sleuthing!

I didn't come up with any values as you did, but I have found inn my old equivalents book 4 substitutes namely 2N5047, 2N3921-2, 2N3954-8 and BFQ10-16, sadly my book gives no specs, but maybe you are familiar with one of these?

That info you posted is very interesting and useful, its also nice to know that its not only me who's had problems with the scopex! ;)

BTW I ordered from Rapid, but alas they had none of the above, infact they only had a few Junction Fets, so I ordered a couple of each. :)

Now I just have to wait for the postman.

Regards..............Al
 
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Hi Eric,

I also have been sleuthing!

I didn't come up with any values as you did, but I have found inn my old equivalents book 4 substitutes namely 2N5047, 2N3921-2, 2N3954-8 and BFQ10-16, sadly my book gives no specs, but maybe you are familiar with one of these?

BTW I ordered from Rapid, but alas they had none of the above, infact they only had a few Junction Fets, so I ordered a couple of each. :)

Now I just have to wait for the postman.

Regards..............Al

hi Al,

Member 'on1aag' has posted a link for a U421, a metal case version of the E421.

From a quick look at the datasheet the FET has a specialised spec.

I have attached it to this post.
 

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  • U421.pdf
    76.3 KB · Views: 282
Tried for a quote

Hi Eric,

I just tried to get a quote for a U421 but the site just gets stuck then returns a page of errors, maybe its my computer or connection, have a go see if you have better luck.

Al
 
Hi Eric and all,

Just got my order from Rapid!

Would someone please go to the rapid site here - **broken link removed** and see if they think the LM3046 shows what package its in?

I expected a DIP IC but got damn surface mount ones! I know this wouldn't be a problem if you were building a circuit, but as a replacement for a DIP IC it makes life a lot more tedious!

So it may be some time Eric before I get the 3046s in the scope! That just serves me right for thinking I could just plug them in and let you know the results.

Any Ideas on the quickest way of converting SM to DIP? If they weren't socketed I would probably have just soldered some extenions on the legs, but the sockets make this a bit iffy.

Anyway I will get my thinking cap on and see if I can come up with an idea for it, but if anyone has done it before successfully let me know please.

Al :confused:
 
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Hi Eric,

Yes I had thought about something in that line, there are also many little adaptor boards on the net, I actually have some that make 8pin SM into DIPs, but sadly no 14s, looks like I will have to make some similar little boards, but that means designing and then etching and drilling and it all takes time, and I am anxious to try the scope.

But as you said it happens, so I will get to designing some boards, maybe I will get to check the scope sometime today if all goes well.

BTW did you notice that the LM3046s were the only ones without an accompanying datasheet, bet its the only component on rapid without one, or I would have looked and seen they were SM. DOH!

Yep, like the farnell ones - just seen the edit :)

Regards...............Al
 
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Hi Eric,

Yes I had thought about something in that line, there are also many little adaptor boards on the net, I actually have some that make 8pin SM into DIPs, but sadly no 14s, looks like I will have to make some similar little boards, but that means designing and then etching and drilling and it all takes time, and I am anxious to try the scope.

But as you said it happens, so I will get to designing some boards, maybe I will get to check the scope sometime today if all goes well.

BTW did you notice that the LM3046s were the only ones without an accompanying datasheet, bet its the only component on rapid without one, or I would have looked and seen they were SM. DOH!

Regards...............Al

hi,
Datasheet here:;)


https://uk.farnell.com/jsp/search/b...nsearch_001&Ntt=LM3046&Ntx=&_requestid=247129
 
Thanks Eric,

At least the pinouts are the same for the SM and DIPs, praise be for small mercy eh! hehehe

Al
 
I'm getting happier! :)

Hi Eric,

I made some makeshift adaptors (which miraculously worked) and put in the CAs as per your orientation and I now have 1 trace mid screen, 2 traces when I press locate!

The second trace is much lower than the first and I cannot control either one with the vertical adjusters, but at least I have 2 traces then.

You have so far been spot on in your remote diagnostics!

What do you reccommend as the next move?

Should I reconnect the 4 components I uncoupled?

I shall await your next words of wisdom! As it happens I am on holiday this week so I have had plenty of time for experimentation, I'm off till tuesday, and am I ever glad we couldn't get it at our usual holiday place at blackpool, that would have been a real wet experience!

Regards annd thanks as ever..............Al :)
 
Hi Eric,

I made some makeshift adaptors (which miraculously worked) and put in the CAs as per your orientation and I now have 1 trace mid screen, 2 traces when I press locate!

The second trace is much lower than the first and I cannot control either one with the vertical adjusters, but at least I have 2 traces then.

You have so far been spot on in your remote diagnostics!

What do you reccommend as the next move?

Should I reconnect the 4 components I uncoupled?

I shall await your next words of wisdom! As it happens I am on holiday this week so I have had plenty of time for experimentation, I'm off till tuesday, and am I ever glad we couldn't get it at our usual holiday place at blackpool, that would have been a real wet experience!

Regards annd thanks as ever..............Al :)

hi Al,
Its back to re-taking voltage measurements at the points covered previously.

Make sure ALL the parts you have temporarily lifted out of the pcb are back in place.
Mark up a the schematic dwg and post it.
BTW: look at the errata at the end of the manual text, some voltages are different from the dwg..

Blackpool and Fleetwood are my old stomping ground.

We did all the surveying hardware and software for Fleetwood harbour for a number of years.
 
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Update for Eric

Hi Eric,

Components back in place and B trace working and adjustable!

A trace still only visible with locate.

Now starting testing voltges.

Al
 
Results

Hi Eric,

Results as follows:-

1 = -1v3
2 = +5v6
3 = +15v1
4 = +15v1
5 = +15v1
6 = +180v
7 = +180v
8 = +14v4 measured on collector
9 = +14v4 measured on collector
10 = -15v1 one end 0v other end
10a = 15v1 both ends

I am not an expert by any means, but I have noticed that one of the +15v1 seems to be -15v1 on the drawing is this an error or a fault on board?

Hoping these will help solve my problem...........Al :)
 
Have you changed the FET yet? - that's always been the most likely problem.

Hi Nigel,

No haven't changed the fet mate, its a dual fet and a strange one at that, seems very difficult to source, I was talking to Eric on the possibility of replacing it with 2 singles, but this may be difficult due to the characteristics of the original fet, have a look at the sheet for it.

If you have any ideas on a replacement I would be only too glad to implement them mate. :)
 
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