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Author Topic: Hameg 408-1A  (Read 4209 times)

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Offline Specmaster

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Re: Hameg 408-1A
« Reply #125 on: Today at 06:45:46 AM »
Great, good pointers from Sky that also point you to the SMPS FB circuitry that I mentioned in reply #77.
R462 out of spec will certainly bugger things up and all those divider resistors need be checked.

Good to know you can get another PSU if needed.  :-+
[/quote
Yes you did indeed, I thought the FB was the IC's, never gave that section of the circuit any great thought, silly I know when you look at it, all the voltages are present there (or rather they should be haha).

As to the new psu if required, do you really think the scope is worthy of that kind of money being spent on it? Or would it be better put towards something a little newer and more advanced?
 

Online tautech

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Re: Hameg 408-1A
« Reply #126 on: Today at 07:15:36 AM »
Great, good pointers from Sky that also point you to the SMPS FB circuitry that I mentioned in reply #77.
R462 out of spec will certainly bugger things up and all those divider resistors need be checked.

Good to know you can get another PSU if needed.  :-+
Yes you did indeed, I thought the FB was the IC's, never gave that section of the circuit any great thought, silly I know when you look at it, all the voltages are present there (or rather they should be haha).

As to the new psu if required, do you really think the scope is worthy of that kind of money being spent on it? Or would it be better put towards something a little newer and more advanced?
Proceed with this repair........remember the SMPS is shutting down as it should in a fault condition, the FB for this to happen is likely coming only from the part of the circuit currently being focussed on. A few dividers and a couple of transistors shouldn't be hard to get right now that the componentry around the SMPS IC has been carefully checked.
This scope looks like a very nice unit and if it is close to being fixed and proves it is indeed a top CRO then the PSU could be well worth the money.
Once you have this and the Phillips fixed you can make the choice which to keep and maybe fund the PSU from the sale of the Phillips.
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Offline Specmaster

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Re: Hameg 408-1A
« Reply #127 on: Today at 07:36:37 AM »
Great minds think alike.. I already have the Philips on Ebay, while I was waiting around for the various parts to arrive for the Hameg, I looked at the philips and thought it was performing reasonably well. Checked the calibration with my tester and it seems to be so close to being right that it wasn't worth while cracking it open to adjust it. Run through all the various parts that I could with it and it seems to be working well so it's up for sale.

I have that sweet little Hitachi V525 (50Mhz) that I got a couple of weeks ago, also a basic Rapid Electronics 25Mhz one in mint condition only a couple of years old which I doubt has been used for more than a few hours, along with a lovely old 60Mhz Iwatsu SS-5710 which is a 4 tracer and a Goldstar OS-9100D (100Mhz) which is a 3 tracer so with the Hameg (I'd have to keep it after all the work that has gone into it now and does have that storage capability even if it is basic when compared to a DSO) I don't think I'd need more than those haha.

I know, never say never, I just enjoy working with them and putting them back into some sort of usable state rather than letting them going for landfill.
 

Online tautech

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Re: Hameg 408-1A
« Reply #128 on: Today at 07:50:54 AM »
I know, never say never, I just enjoy working with them and putting them back into some sort of usable state rather than letting them going for landfill.
Me too.....in the past.
That's how I got into the industry and repairs of TE is very satisfying.
I used to put all the manuals I could find onto a CD, provide new cheapie probes and resell them.
I got enough back that I could buy more broken units, rinse and repeat.

Whatsmore on this forum we provide a valuable resource for those with similar problems and learn a lot along the way too.
Your detailed posts and regular updates make threads like this a good read.

I've still got a few old 'not right' CRO's tucked away for repair threads.......if I ever get around to them.  ::)
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