Phase Linear 2000 op-amp upgrade

[premiumplus]

View attachment 11685

When I worked at Siemens Automotive I was a failure analysis engineer. I specialized in root cause analysis for anti-lock brakes and air bag deployment modules. We did a lot of SMT soldering too, and I don't miss it one bit. If you don't have the tools, don't try it! We used a preheat plate and that made things easier, but it's definitely a different process than regular through hole soldering.
We had Metcal equipment too, Joe. Good stuff.

 

[Coldsmoke]

Installed the new dual op-amps with Brown Dog adaptor. Easiest upgrade I've ever done.
Couple of taps with the hammer and success. Sounds great. Now to find the mylar caps.
Thanks Lee

Hello there,

I received oday my little browndog thing : I am maybe missing something obvious, but, I can't figure in wich direction I'm supposed to insert te adaptator as I can't see any kind of poka yoke to help with ...

Any tip?

Thanks a lot in advance

 

[laatsch55]

I should have said buy the "mounted" option.... as I have never surface mount soldered I really have no help to offer here...

 

[Gepetto]

Hello there,

I received oday my little browndog thing : I am maybe missing something obvious, but, I can't figure in wich direction I'm supposed to insert te adaptator as I can't see any kind of poka yoke to help with ...

Any tip?

Thanks a lot in advance

Send some photos Florian to help explain what you mean please.

 

[laatsch55]

Florian there is an indicator on the mounted option. Did you buy the adapter with the op-amps mounted?

 

[laatsch55]

Pin number 1 is a square tinned hole, the rest are round...on BOTH options, there is that square hole indicator....

 

[Coldsmoke]

Pin number 1 is a square tinned hole, the rest are round...on BOTH options, there is that square hole indicator....

Hello Lee, I bought the mounted option of course as advised : I hadn't noticed the little square thing, thanks for that. I am more used to the rounded footprint at one end of the body of the OPA.


BTW, a quick update on my 'restoration':
- I'm almost done with replacing all the resistors with 1% ones
- I read on a Joe's comment that the use of the 33k resistor on the volume pot could cause some troubles, so I won't replace it
- I couldn't find .0027uF 150V so I'm planing to mount .03uF 220V on the top pot ends
- Last thing : I couldn't find any low intensity white led so I'm trying to figure the value of the resistor that I should place between the TIS97 and the led to lower its insentity, say of 50% or so... Any clue?

 

[laatsch55]

Not offhand no, but Ohm's law still works. If you want to cut the current in half, I would double the resistance...

 

[Coldsmoke]

Not offhand no, but Ohm's law still works. If you want to cut the current in half, I would double the resistance...

Ah ah Thanks Lee you probably think that I'm such a goat with the ABC's

My point was rather : Can I assume that the instnsity is a direcet linear function of the amperage ....? I think I just have to try .... I'll start with doubling the resistance (122 O if I'm correctly applying my ohm law for a 2.2 V 18mA) : ))

 

[Gepetto]

Not offhand no, but Ohm's law still works. If you want to cut the current in half, I would double the resistance...

Trial and error to your liking. LED light output is not very linear with current especially at the low end. Clip on a jumper and try various higher resistor values until you find one you like and then perform the solder replacement.

 

[laatsch55]

If one was to make an assumption that's as good as any.....is illumination linear? Good question...

 

[Coldsmoke]

If one was to make an assumption that's as good as any.....is illumination linear? Good question...

Yep sorry, sometimes I just write what I have in my head without realy thinking... It wasn't really a question, let's try, :]

 

[Gepetto]

If one was to make an assumption that's as good as any.....is illumination linear? Good question...

It is not Lee...

 

[laatsch55]

Yep sorry, sometimes I just write what I have in my head without realy thinking... It wasn't really a question, let's try, :]

I know it wasn't really a question, I took it as rhetorically.....




Joe, Thank you!! Now we know. I imagine optics and illumination has it's own can of worms to deal with...

 

[gadget73]

Sounds like a good use for a variable resistor with 1/2w or so dissapation rating. Adjust until it looks right, measure it, stab in the closest standard value fixed resistor. Bit of a hack way to do it, but "cheat to win" as they say.