Reply by John Larkin ●December 17, 20172017-12-17
On Sun, 17 Dec 2017 15:31:38 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:


>On 12/16/2017 10:23 PM, krw@notreal.com wrote:
>> On Sat, 16 Dec 2017 11:51:59 -0800, John Larkin
>> <jjlarkin@highlandtechnology.com> wrote:
>> 
>>> On Sat, 16 Dec 2017 19:18:39 GMT, Steve Wilson <no@spam.com> wrote:
>>>
>>>> John Larkin <jjlarkin@highlandtechnology.com> wrote:
>>>>
>>>>> There was Halted and Haltek. That always confused me.
>>>>
>>>> Yes, they split sometime in the past. I seem to recall that Halted had a lot
>>>> more and better junk.
>>>
>>> For serious, dangerously-stacked junk, there was Mike Quinn, in the
>>> quonset hut off the runway at the Oakland airport. Hardhat advised.
>>>
>>> I never understood strip joints, or prostitution. How could you be
>>> sure she truly loves you?
>> 
>> As long as you're spreading around dead presidents, she truly loves
>> you.
>> 
>>> The strip joints generally had bad food anyhow.
>> 
>> You're not supposed to eat the food.
>>>
>>> There were two classes of guys in SV, back when. The engineers went to
>>> lunch at restaurants and dressed up a bit. The techs drove pickups,
>>> pretended to be cowboys, and went to lunch at the strip clubs.
>> 
>> Never considered eating lunch, or anything else, at a strip club.
>> Haven't seen one that serves food.
>> 
>
>There was a weird period in the early '80s when seemingly all the bars 
>in Vancouver had strippers at lunch time.
>
>Cheers
>
>Phil Hobbs


Men are weird.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics
Reply by ●December 17, 20172017-12-17
On 17 Dec 2017 21:09:53 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:


>On 2017-12-15, Steve Wilson <no@spam.com> wrote:
>> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>
>>> On 12/15/2017 02:48 PM, Steve Wilson wrote:
>>>> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>>  
>>>>> On 12/15/2017 01:24 PM, Steve Wilson wrote:
>>>>> And lots of parts are likely to be damaged during test--back in the
>>>>> day, JAN TX screened transistors were notoriously less reliable than
>>>>> the COTS ones due to all the extra handling. 
>>  
>>>> Bad handling procedures from long ago, and less reliable designs. This
>>>> can kill parts during assembly. Modern parts and procedures should be a
>>>> lot more reliable. 
>>  
>>> Maybe.  But the sheer amount of fixturing and labour involved in testing
>>> every kind of part that we use would make the whole thing uneconomic.
>>> Parts are cheap, but labour is expensive, and fixtures take up a lot of
>>> space.
>>  
>> I've been thinking about that. An automated tester shouldn't be very 
>> complicated. Separate jigs for diferent size smd's. A little stepper to 
>> advance the reel to the next component. A fast precision LCR meter to 
>> measure the components. 0.1% should be good enough for most parts. 
>>
>> Perhaps a small Teensy or Arduino to log the measurements and step the 
>> reel. Some of the guys on Hackaday do fantastic work on small mechanisms.
>>
>> One problem is to find a way to mark bad components. If the test is fast 
>> enough, maybe test the whole reel. 3600 parts at 100ms per part would only 
>> take 6 minutes.
>
>hit it with a pin, or a blast of air from underneath and eject it from the tape?
>The assembly machine will assume it fumbled the part and advance the
>tape and try again.
>
>hit it with glue from below or above so that the assembly machine can't
>extract it from the tape, or so that it sticks the the cover strip and
>vacates the tape early...
>
>Cut a notch, or add ink, between sprocket holes? but then the assembly feeder would
>need to know what the notch or ink means


Just log the bad parts and forward the information to the pick&place
machine.  Or, just buy good parts in the first place.
Reply by Jasen Betts ●December 17, 20172017-12-17
On 2017-12-15, Steve Wilson <no@spam.com> wrote:

> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>
>> On 12/15/2017 02:48 PM, Steve Wilson wrote:
>>> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
>  
>>>> On 12/15/2017 01:24 PM, Steve Wilson wrote:
>>>> And lots of parts are likely to be damaged during test--back in the
>>>> day, JAN TX screened transistors were notoriously less reliable than
>>>> the COTS ones due to all the extra handling. 
>  
>>> Bad handling procedures from long ago, and less reliable designs. This
>>> can kill parts during assembly. Modern parts and procedures should be a
>>> lot more reliable. 
>  
>> Maybe.  But the sheer amount of fixturing and labour involved in testing
>> every kind of part that we use would make the whole thing uneconomic.
>> Parts are cheap, but labour is expensive, and fixtures take up a lot of
>> space.
>  
> I've been thinking about that. An automated tester shouldn't be very 
> complicated. Separate jigs for diferent size smd's. A little stepper to 
> advance the reel to the next component. A fast precision LCR meter to 
> measure the components. 0.1% should be good enough for most parts. 
>
> Perhaps a small Teensy or Arduino to log the measurements and step the 
> reel. Some of the guys on Hackaday do fantastic work on small mechanisms.
>
> One problem is to find a way to mark bad components. If the test is fast 
> enough, maybe test the whole reel. 3600 parts at 100ms per part would only 
> take 6 minutes.


hit it with a pin, or a blast of air from underneath and eject it from the tape?
The assembly machine will assume it fumbled the part and advance the
tape and try again.

hit it with glue from below or above so that the assembly machine can't
extract it from the tape, or so that it sticks the the cover strip and
vacates the tape early...

Cut a notch, or add ink, between sprocket holes? but then the assembly feeder would
need to know what the notch or ink means


-- 
This email has not been checked by half-arsed antivirus software
Reply by Phil Hobbs ●December 17, 20172017-12-17
On 12/16/2017 10:23 PM, krw@notreal.com wrote:

> On Sat, 16 Dec 2017 11:51:59 -0800, John Larkin
> <jjlarkin@highlandtechnology.com> wrote:
> 
>> On Sat, 16 Dec 2017 19:18:39 GMT, Steve Wilson <no@spam.com> wrote:
>>
>>> John Larkin <jjlarkin@highlandtechnology.com> wrote:
>>>
>>>> There was Halted and Haltek. That always confused me.
>>>
>>> Yes, they split sometime in the past. I seem to recall that Halted had a lot
>>> more and better junk.
>>
>> For serious, dangerously-stacked junk, there was Mike Quinn, in the
>> quonset hut off the runway at the Oakland airport. Hardhat advised.
>>
>> I never understood strip joints, or prostitution. How could you be
>> sure she truly loves you?
> 
> As long as you're spreading around dead presidents, she truly loves
> you.
> 
>> The strip joints generally had bad food anyhow.
> 
> You're not supposed to eat the food.
>>
>> There were two classes of guys in SV, back when. The engineers went to
>> lunch at restaurants and dressed up a bit. The techs drove pickups,
>> pretended to be cowboys, and went to lunch at the strip clubs.
> 
> Never considered eating lunch, or anything else, at a strip club.
> Haven't seen one that serves food.
> 


There was a weird period in the early '80s when seemingly all the bars 
in Vancouver had strippers at lunch time.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
Reply by ●December 16, 20172017-12-16
On Sat, 16 Dec 2017 11:51:59 -0800, John Larkin
<jjlarkin@highlandtechnology.com> wrote:


>On Sat, 16 Dec 2017 19:18:39 GMT, Steve Wilson <no@spam.com> wrote:
>
>>John Larkin <jjlarkin@highlandtechnology.com> wrote:
>>
>>> There was Halted and Haltek. That always confused me. 
>>
>>Yes, they split sometime in the past. I seem to recall that Halted had a lot 
>>more and better junk.
>
>For serious, dangerously-stacked junk, there was Mike Quinn, in the
>quonset hut off the runway at the Oakland airport. Hardhat advised.
>
>I never understood strip joints, or prostitution. How could you be
>sure she truly loves you? 


As long as you're spreading around dead presidents, she truly loves
you.


>The strip joints generally had bad food anyhow.


You're not supposed to eat the food.

>
>There were two classes of guys in SV, back when. The engineers went to
>lunch at restaurants and dressed up a bit. The techs drove pickups,
>pretended to be cowboys, and went to lunch at the strip clubs.


Never considered eating lunch, or anything else, at a strip club.
Haven't seen one that serves food.
Reply by whit3rd ●December 16, 20172017-12-16
On Saturday, December 16, 2017 at 4:49:41 PM UTC-8, John Larkin wrote:


> The bottom line is to keep them really dry before soldering.
> This is funny:
> 
> https://www.dropbox.com/s/q8pzdwhdfnkqnvn/Film_Cap_1.jpg?raw=1


It'd be even more dramatic if you'd stuck a few popcorn kernels
next to the surface-mount.   Same effect, really, but butter improves
the alternate components.
Reply by John Larkin ●December 16, 20172017-12-16
On Sun, 17 Dec 2017 00:01:56 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:


>On 16/12/17 16:49, John Larkin wrote:
>> On Sat, 16 Dec 2017 13:04:42 GMT, Steve Wilson <no@spam.com> wrote:
>>
>>> John Larkin <jjlarkin@highlandtechnology.com> wrote:
>>>
>>>> On Sat, 16 Dec 2017 03:01:23 GMT, Steve Wilson <no@spam.com> wrote:
>>>
>>>>> And that's only one of dozens of details I need to take care of.
>>>
>>>> Skip that one; it's a waste of time.
>>>
>>> The more I think of it, a better place to do the test is at the pick and
>>> place, just before the component is placed on the pcb. Then I will get a
>>> record of the value of each component and the location. It would take only a
>>> bit of software to convert the location to a reference designation.
>>>
>>> An earlier poster mentioned another machine that does this, but he didn't
>>> know if they actually measured the value.
>>
>> Our Universal machine does optical inspection, not electrical, on
>> every part.
>>
>> The more real problem isn't DOAs, it's parts damaged in process, or by
>> electrical abuse. Lead-free temperature profiles are bad, as is water
>> washing (for some parts) or solvent wash (for others).
>>
>> We've recently had problems with presumably sealed relays.  The
>> conclusion: never get them near water.
>>
>> We ran a couple of these boards
>>
>> https://www.dropbox.com/s/2avvklzwtzc8rz4/P951_E1.JPG?raw=1
>>
>> (and then threw them away)
>>
>> through various soldering and cleaning cycles. We have setups that can
>> measure contact resistance and leakage on almost every contact on the
>> board.
>>
>>
>
>
>I thought as much. I've got the same problems, no doubt: Unreliable
>contacts. My circuit isn't very sensitive to leakage, but there may
>be that, too.
>
>Jeroen Belleman


We had some leakage and some high-resistance contacts, apparently
corrosion. We had one board that we were successively abusing, and the
last cycle was water wash then another pass through the reflow oven,
something that would never be done in real life. All the relays came
out domed, convex on top. 

The bottom line is to keep them really dry before soldering. Original
packaging, dry cab, maybe bake if they have been out.

They seem fine with a leaded or lead-free temp profile, as long as
they are dry before soldering and solvent washed after.

https://www.dropbox.com/s/oih7wl212kgukxr/Dry.jpg?raw=1

Note that the lid is an active part of the mechanism, so it doesn't
want to be domed.

This happened after extreme abuse, but it shows that it is possible to
force water into a "sealed" relay.

https://www.dropbox.com/s/w1l7qcu9m7c2i48/WET.jpg?raw=1

Another part we had trouble with were surface-mount film caps, which
delaminate and trap water. We don't use them any more.

This is funny:

https://www.dropbox.com/s/q8pzdwhdfnkqnvn/Film_Cap_1.jpg?raw=1




-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics
Reply by Jeroen Belleman ●December 16, 20172017-12-16
On 16/12/17 16:49, John Larkin wrote:

> On Sat, 16 Dec 2017 13:04:42 GMT, Steve Wilson <no@spam.com> wrote:
>
>> John Larkin <jjlarkin@highlandtechnology.com> wrote:
>>
>>> On Sat, 16 Dec 2017 03:01:23 GMT, Steve Wilson <no@spam.com> wrote:
>>
>>>> And that's only one of dozens of details I need to take care of.
>>
>>> Skip that one; it's a waste of time.
>>
>> The more I think of it, a better place to do the test is at the pick and
>> place, just before the component is placed on the pcb. Then I will get a
>> record of the value of each component and the location. It would take only a
>> bit of software to convert the location to a reference designation.
>>
>> An earlier poster mentioned another machine that does this, but he didn't
>> know if they actually measured the value.
>
> Our Universal machine does optical inspection, not electrical, on
> every part.
>
> The more real problem isn't DOAs, it's parts damaged in process, or by
> electrical abuse. Lead-free temperature profiles are bad, as is water
> washing (for some parts) or solvent wash (for others).
>
> We've recently had problems with presumably sealed relays.  The
> conclusion: never get them near water.
>
> We ran a couple of these boards
>
> https://www.dropbox.com/s/2avvklzwtzc8rz4/P951_E1.JPG?raw=1
>
> (and then threw them away)
>
> through various soldering and cleaning cycles. We have setups that can
> measure contact resistance and leakage on almost every contact on the
> board.
>
>



I thought as much. I've got the same problems, no doubt: Unreliable
contacts. My circuit isn't very sensitive to leakage, but there may
be that, too.

Jeroen Belleman
Reply by Steve Wilson ●December 16, 20172017-12-16
John Larkin <jjlarkin@highlandtechnology.com> wrote:


> I never understood strip joints, or prostitution. How could you be
> sure she truly loves you? The strip joints generally had bad food
> anyhow.


Beer goggles.
 

> There were two classes of guys in SV, back when. The engineers went to
> lunch at restaurants and dressed up a bit. The techs drove pickups,
> pretended to be cowboys, and went to lunch at the strip clubs.


I used to take customers to the Brass Rail for lunch. They had a fabulous 
buffet with some of the best beef roast I have ever found. The girls would 
serve beer topless, but that changed later. One girl could take a full large 
mug of beer under one tit and pour it into a drinking glass under the other 
tit. That always drew applause.

My customers loved it.
Reply by John Larkin ●December 16, 20172017-12-16
On Sat, 16 Dec 2017 19:18:39 GMT, Steve Wilson <no@spam.com> wrote:


>John Larkin <jjlarkin@highlandtechnology.com> wrote:
>
>> There was Halted and Haltek. That always confused me. 
>
>Yes, they split sometime in the past. I seem to recall that Halted had a lot 
>more and better junk.


For serious, dangerously-stacked junk, there was Mike Quinn, in the
quonset hut off the runway at the Oakland airport. Hardhat advised.

I never understood strip joints, or prostitution. How could you be
sure she truly loves you? The strip joints generally had bad food
anyhow.

There were two classes of guys in SV, back when. The engineers went to
lunch at restaurants and dressed up a bit. The techs drove pickups,
pretended to be cowboys, and went to lunch at the strip clubs.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics