Formac G3 ZIF carrier - Repair

[Kai Robinson]

So a while back, I bought one of these:

a Formac ProG3 400-50 ZIF carrier card.

It came with the ZIF G3 daughtercard, but no heatsink. I finally tracked down one from a B&W G3 and mounted it. However, after years of use, this sockets mounting ears have become horribly brittle.

Superglue and baking soda were attempted but it doesn't hold.

Still, thanks to our thread here: https://tinkerdifferent.com/threads/macintosh-connector-part-numbers.135/page-2

I picked up a couple of identical, brand new, in box PGA-288 sockets from Germany!

Time to bust out the hot air for this one, but, I'll try and use wick and the iron first, as the pins on the old socket hardly protrude through the PCB.

One other advantage of the new socket is that it has more mounting tabs, for better heatsink attachment.

 

[trag]

How will you solder the new one in? Paste and hot air, or pencil and one pin at a time? Or something else?

Curious.

Good luck.

 

[Kai Robinson]

I have some really nice kester solder - just pin by pin with the iron for that - i don't get on well with paste and no stencil!

 

[trag]

I have some really nice kester solder - just pin by pin with the iron for that - i don't get on well with paste and no stencil!

Yeah, I've tried paste with no stencil in the past and mostly made a mess. It's made me reluctant to try it with a stencil. I gather that (with stencil) works out better for you?

That's a lot of pins to solder by hand, although I expect you'll get into a rhythm and it will go pretty fast. Good luck and please let us know how it turns out.

 

[Kai Robinson]

I've spent 4 hours so far trying to remove it with little success so far. I've currently got it on a cast iron hotplate in the kitchen. I fluxed the crap out of the pins and methodically went over each one with the iron set to 380*c and some 2.0mm GootWick, and have cleared each individual hole. However, i am now at the point where i think that epoxy or some other sort of adhesive was used as underfill, as even then, the socket isn't lifting hardly at all.

Hotplate and slow heating it should hopefully loosen it!

 

[Kai Robinson]

IT WORKED! Full heat on the cast iron helped the socket just pull right out - however, in the process, the PCB lifted about 1cm and dropped...and then flung off the bus switches and a few passives - all are intact, no bent legs, just means i have to solder some TSSOP-48 parts! No trace damage either, that i can see. The board is in the ultrasonic now - will upload pics in a minute

Let this be a lesson - get an IR board pre-heater

 

[Kai Robinson]

...Passives on, but i've lost two of the diodes and a resistor in the kitchen somewhere - no biggie, right? Well, the diodes are marked J5 which equates to a ZC834 single diode. Which are obsolete. And i can't find a suitable replacement as they're variable capacitance...

The other issue is there are now bent pins on some of these bus switch IC's (the QS32X384's), i've bought some more, but they're just so fragile and tiny - without a microscope i doubt i can go any further.

Unless @Branchus or @max1zzz want to earn some beer tokens

 

[Kai Robinson]

Can someone check me on this - i've found some parts that might work, and match at least some specs. I've included the original ZC834 datasheet, but also linking on digikey to the other parts:

https://www.digikey.co.uk/en/products/detail/macom-technology-solutions/MAVR-000401-0287AT/12627541
https://www.digikey.co.uk/en/products/detail/microchip-technology/KVX31S1-23-0/13175024

Looking at Q factor there - more than capacitance, as this is for the VCO / PLL circuit.

 

[max1zzz]

Unless @Branchus or @max1zzz want to earn some beer tokens

Your always welcome to send it my way, those TSSOP48 parts are no match for my microscope and FX-951

 

[Kai Robinson]

Haha - i'll finish the order of the QS32X348's and send it along with those - I just need to find the right diodes.

 

[trag]

Your always welcome to send it my way, those TSSOP48 parts are no match for my microscope and FX-951

What kind of microscope do you have? We have this white stereoscope at work and I can never remember the name. Nautilaus or Unicorn or Hydra or something. They're fairly pricey though.

 

[max1zzz]

What kind of microscope do you have? We have this white stereoscope at work and I can never remember the name. Nautilaus or Unicorn or Hydra or something. They're fairly pricey though.

This is the one I got: https://www.ebay.co.uk/itm/401906276099 It's pretty much the cheapest stereo microscope with a boom arm amscope sells but I have been very happy with it so far

 

[Kai Robinson]

This is the one I got: https://www.ebay.co.uk/itm/401906276099 It's pretty much the cheapest stereo microscope with a boom arm amscope sells but I have been very happy with it so far

*sneaks this onto his wife's eBay basket*

 

[Branchus]

Unless @Branchus or @max1zzz want to earn some beer tokens

You know I'm always happy to help if I can!

 

[trag]

This is the one I got: https://www.ebay.co.uk/itm/401906276099 It's pretty much the cheapest stereo microscope with a boom arm amscope sells but I have been very happy with it so far

Excellent. Doesn't ship to the USA, but I entered the Item title in the USA Ebay site, and received a dizzying array of results.

The exact one you got is available. But then, there are all the other results....

https://www.ebay.com/sch/i.html?_fr...icroscope+with+Double+Arm+Boom+Stand&_sacat=0

The low end magnification is available from 3.5X to 7X and upper end 45X to 180X. There are some with LED ring lights, or lights on wands, and binocular vs. trinocular, and others that include digital cameras ranging from 1.3 megapixels up to 14 megapixels.

And prices are all over too of course.

I'll be like that donkey with two bales of hay. I'll never buy a microscope for want of the ability to settle on one model.

Ah, the one at work is called "Mantis". Starts at about $1600.

https://www.tequipment.net/Vision-E...gNtwaZ7o94P15fc9T7tq5X7XVW3uS0CYaAkeJEALw_wcB

 

[Kai Robinson]

@max1zzz I just ordered the last 41 of the QS32X384Q1G's from mouser before they go obsolete! Rather than order just enough, i went for all of them.

The ZC834's are on the way as well, still up to the task?

 

[max1zzz]

I just ordered the last 41 of the QS32X384Q1G's from mouser before they go obsolete! Rather than order just enough, i went for all of them.

I've been there! I have a full 5k reel of 4k7 0603's because I needed about 4 once

The ZC834's are on the way as well, still up to the task?

Sure!