[sdiy] PAiA 2720/R rebuild

Dave Brown davebr at earthlink.net
Mon Oct 27 22:09:24 CET 2014


I wasn't meaning to rag on the original kit builder.  We all have to start
somewhere and I shudder to think what my first soldering jobs were like.
What I don't get though are people who don't mount components flush to the
PCB.  I still get DIY repairs where the parts are anywhere from 1/4 to 1/2"
off the PCB.  I think the biggest issue for first time kit builders is the
wrong soldering iron.  When I started many years ago I started with a gun,
albeit a small gun.  Later I upgraded to a pencil type but even that wasn't
very good.  It had copper tips that just wore out so it was hard to heat a
pad.  Finally I found some gold plated tips that worked quite well and I
used that iron for many years.

I didn't built too much PAiA stuff but I built a lot of Heathkit and SWTPC
kits.  Most were pretty good but some of the Heathkit stuff was bare copper
PCBs and I remember leaving a lot of flux on those.  I imagine they look
pretty bad now as the copper will have corroded fingerprints all over it.
When I make a DIY on a copper breadboard I always solder the complete pad so
there is no exposed copper.  Of course I would rather have a plated
breadboard but sometimes I can't find those in the form factor I need.

Dave

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Tom Wiltshire
Sent: Monday, October 27, 2014 12:04 PM
To: John Speth
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] PAiA 2720/R rebuild

Absolutely agree. Looking at my old stomp boxes with the back off is like a
soldering horror show, but you've gotta learn somehow, and getting stuck in
is one of the best ways.
great to
I doubt many PAIA synths ever looked so good. Nice work indeed.

Tom

On 27 Oct 2014, at 17:45, John Speth <jspeth at avnera.com> wrote:

> I too drooled over the affordable PAIA goods as a teenager.  My paper 
> route was not enough to fund my desire.  But I'm sure you can forgive 
> the poor build quality.  Whoever built it was learning what we've all 
> developed passion for.  I still have some of my first-built stuff from 
> 40 years ago (the ones that actually worked).  They're far from high 
> build quality too. :)
> 
> My hat's off to your for tackling that project!  Nice work.
> 
> JJS
> 
>> Yeah, poor soldering on DIY kit. I was restoring Formant once (well, 
>> I
> still
>> am) and literally every solder joint on every board had to be sucked 
>> and resoldered. All panel wiring removed and redone from scratch as 
>> it was
> sooo
>> wrong it hurts.
>> 
>> Anyway, great job on your PAiA! I can imagine how tough that was.
>> But I miss "before/after" photos, they make any restoration report
> great.
>> 
>> Roman
>> 
>> W dniu 2014-10-27 00:30, Dave Brown pisze:
>>> He didn't on this one.  I've never seen so much flux all over
> everything.
>>> Leads extended through quite far, were bent over, and about 3X too 
>>> much solder was used.  I don't think it was acid core solder but it 
>>> had about that much flux on it.  I ended up sucking every pad and 
>>> resoldering and fixing the pads that had lifted.  I think the sheer 
>>> weight of the solder on the underside was enough to lift the pads!
>>> 
>>> Dave
>>> 
>>> -----Original Message-----
>>> Wow!  Looks great!  That was on my Christmas wish list from the age 
>>> of
>>> 12 (I turn 50 on Wednesday).  Santa never brought it.  I did try to 
>>> build a Gnome with a friend in 1976, and failed utterly (he actually 
>>> bought it, and was too impatient to use flux with the solder - every 
>>> solder joint was stone cold).  I didn't attempt Synth DIY again 
>>> until 2008.  Now, of course, I look at the PAiA stuff, and can't 
>>> believe how cheap it looks and how simple it is.
>>> 
>>>> -----Original Message-----
>>>> In case anyone is interested, I just was given a PAiA 2720/R synth 
>>>> that I decided to restore.  A lot of the work was improving the 
>>>> construction techniques of the original builder and dealing with 
>>>> the general degradation of the electro-mechanical parts over time.  
>>>> There is a list on the site but the biggest issue was rebuilding 
>>>> the Pratt and Read keyboard which meant everything had to be 
>>>> disassembled.  The wood cabinet needed some TLC but the only 
>>>> improvements that I made were the increase in PS filter caps and 
>>>> the replacement of just a handful of parts.  Most all the wiring 
>>>> and soldering though had to be redone and it required a lot of 
>>>> cleaning.  The keyboard S&H could benefit from a modern op-amp but I
decided to keep it original.
>>>> 
>>>> Photos and information at
>>>> http://modularsynthesis.com/paia/2700/2700.htm
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