Looking for component source to complete a repair

[greenalien]

I'm trying to fix a Lexicon Reflex reverb, which has a faulty DRAM chip, neatly identified by its internal diagnostic program.

 

Lexicon helpfully supplied me with a copy of the service manual but have otherwise discontinued support for this item, so I need to find the replacement part myself - it's part number is DV41464P-10 - an 18-pin DIL DRAM chip.

 

Searching the internet, lots of component surplus suppliers have this item but all seem to quote a minimum order value of $100 - rather more than I want to spend.

 

Does anyone know a supplier who might sell just a few of these? (4 would be good, if one's gone faulty, might as well replace the lot!)

 

Any help much appreciated - I hate chucking things out if they can be fixed!

[jayselway]

In this sort of situation, These People can be very useful, as they have no minimum order quantity

 

EDIT: Having a fat finger day

[greenalien]

In this sort of situation, These People can be very useful, as they have no minimum order quantity

Thanks very much, looks as though they have what I want - much appreciated.

[greenalien]

As a follow-up, the components duly arrived (4 chips plus postage - £17.33 including VAT!) and I've just finished the repair, so I now have a fully-functional Lexicon Reflex reverb again!

 

I suspect others who own a Reflex may sooner or later get similar problems, as it seems that the DRAM chips used as the 'scratchpad' area don't last indefinitely. Symptoms of the DRAM problem are a regular tapping or breathing noise that repeats every second or so, even with no input to the unit.

(If you own a Reflex, even if it is currently fault-free, might be worth stocking up on spare DRAM as these chips are obsolete and not easy to find - see previous post)

Lexicon kindly supplied me with a PDF copy of the service manual which has full details of the on-board diagnostics - PM me if you want a copy. Apart from that, Lexicon no longer support this unit so repair becomes a DIY job; a professional repair will probably cost more than the value of the unit.

Following the diagnostics clearly identified a DRAM fault - the diagnostics will tell you which chip is faulty but that will only be the first it finds, there may well be more than one so I figured that I might as well replace all 4 chips as a precaution.

Here's my repair method - it'll probably horrify some people, but it works! :

After dismantling the unit, identify the 4 DRAM chips, just behind the vertical LED display board.

As the PCB uses through-plated mounting holes, removing the old chips is an interesting challenge - a normal desoldering pump won't do the job! If you have access to a professional vacuum desoldering station, use that - otherwise, I recommend using a mini-drill with a burr cutter to cut off all the legs from the redundant chips, as close to the body as possible. This makes a fair bit of dust, and needs care not to damage any neighbouring components.

It's then possible to remove each leg separately - long-nosed pliers on one side, soldering iron (1mm bit!) on the other - and only pull gently as it's essential not to damage the holes.

This will then leave most of the holes full of solder but this can easily be removed with a normal desoldering pump.

Took me about 3 hours to do all of this - 72 connections to dismantle and desolder! Anyhow, that's the tricky part done.

Clean up the board to remove any remaining dust, flux and solder blobs and carefully inspect for damage.

Then fit and solder in place 4 x 18-pin DIL sockets for the chips. Double check your soldering, then fit the new chips into the sockets, ensuring they go the right way round, as per the printing on the board. Observe normal anti-static precautions.

Reassemble and test - and good luck!!