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From: Joerg on 27 Mar 2010 11:54
krw(a)att.bizzzzzzzzzzzz wrote:
> On Fri, 26 Mar 2010 07:15:00 -0700, Joerg <invalid(a)invalid.invalid> wrote:
>
>> MooseFET wrote:
>>> On Mar 26, 4:12 am, Hammy <s...(a)spam.com> wrote:
>>>> I haven't placed an order there for a while but I need some HS drill
>>>> bits and they are the only place that has them so I thought I'd look
>>>> around and man I don't know how they stay in business!!! What is their
>>>> mark-up?
>>> Since I know I can find the parts I need on Digikey, I usually don't
>>> worry about what they charge. Prototypes cost far more in labor than
>>> the parts cost. I give the production folks the makers part numbers
>>> for the parts and also the Digikey numbers.
>>>
>> Exactamente. I have yet to find a company on this planet that has a
>> search engine as good as Digikey. This is why I always default to them
>> as well, and so do my clients in the US. I have the impression that 99%
>> plus of the software guys in the database business do not understand how
>> to program a proper search engine, only the guys who set up Digikey do.
>
> Yep. Our Arrow rep is constantly trying to get me to use their search engine.
> I tell him 1) when you make it as easy as DigiKey and 2) that's what I have
> *you* for. I sometimes actually buy from DigiKey but only for small
> quantities and emergencies.
>

My Arrow rep was very honest. "Our search engine isn't as comfy as
Digikey but we can get you a lot of parts others can't", and that's
true. Very good support, Arrow is one of the best.


>>> The reason to give production the Digikey numbers is that it reduces
>>> to nearly zero how often I hear "we can't find the part". Some
>>> production parts get bought from Digikey just because they happen to
>>> be the ones who have them in stock.
>>>
>>>
>>> Digikey also gives a quick path to the maker's data sheets. This
>>> makes designing easier. You can check that the part can be obtained
>>> while also getting the datasheet.
>>
>> I found their prices to occasionally be higher than for example Mouser
>> but not by much. Maybe 10-20% on some parts. But Hammy: It's not
>> necessarily the place to buy tools from, that I never did. Digikey is
>> for electronic parts.
>
> For production quantities I consistently beat DigiKey by 20-50%. Disties get
> special pricing and sometimes disties will cut into that to make a sale. FPGAs
> are notorious for pricing by the customer. Never pay the catalog price for
> 'em.


Being an analog dude I rarely get to deal with FPGA. Except yesterday
when one was unable to drive a bus line. Hurumph!

Did you guys get the transformer issue licked?

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
From: krw on 27 Mar 2010 13:21
On Sat, 27 Mar 2010 08:54:26 -0700, Joerg <invalid(a)invalid.invalid> wrote:

>krw(a)att.bizzzzzzzzzzzz wrote:
>> On Fri, 26 Mar 2010 07:15:00 -0700, Joerg <invalid(a)invalid.invalid> wrote:
>>
>>> MooseFET wrote:
>>>> On Mar 26, 4:12 am, Hammy <s...(a)spam.com> wrote:
>>>>> I haven't placed an order there for a while but I need some HS drill
>>>>> bits and they are the only place that has them so I thought I'd look
>>>>> around and man I don't know how they stay in business!!! What is their
>>>>> mark-up?
>>>> Since I know I can find the parts I need on Digikey, I usually don't
>>>> worry about what they charge. Prototypes cost far more in labor than
>>>> the parts cost. I give the production folks the makers part numbers
>>>> for the parts and also the Digikey numbers.
>>>>
>>> Exactamente. I have yet to find a company on this planet that has a
>>> search engine as good as Digikey. This is why I always default to them
>>> as well, and so do my clients in the US. I have the impression that 99%
>>> plus of the software guys in the database business do not understand how
>>> to program a proper search engine, only the guys who set up Digikey do.
>>
>> Yep. Our Arrow rep is constantly trying to get me to use their search engine.
>> I tell him 1) when you make it as easy as DigiKey and 2) that's what I have
>> *you* for. I sometimes actually buy from DigiKey but only for small
>> quantities and emergencies.
>>
>
>My Arrow rep was very honest. "Our search engine isn't as comfy as
>Digikey but we can get you a lot of parts others can't", and that's
>true. Very good support, Arrow is one of the best.

I just call them and have them look. Yes, they are good. Our Avnet rep is
pretty good too. We get excellent prices from both.

>>>> The reason to give production the Digikey numbers is that it reduces
>>>> to nearly zero how often I hear "we can't find the part". Some
>>>> production parts get bought from Digikey just because they happen to
>>>> be the ones who have them in stock.
>>>>
>>>>
>>>> Digikey also gives a quick path to the maker's data sheets. This
>>>> makes designing easier. You can check that the part can be obtained
>>>> while also getting the datasheet.
>>>
>>> I found their prices to occasionally be higher than for example Mouser
>>> but not by much. Maybe 10-20% on some parts. But Hammy: It's not
>>> necessarily the place to buy tools from, that I never did. Digikey is
>>> for electronic parts.
>>
>> For production quantities I consistently beat DigiKey by 20-50%. Disties get
>> special pricing and sometimes disties will cut into that to make a sale. FPGAs
>> are notorious for pricing by the customer. Never pay the catalog price for
>> 'em.
>
>
>Being an analog dude I rarely get to deal with FPGA. Except yesterday
>when one was unable to drive a bus line. Hurumph!
>
>Did you guys get the transformer issue licked?

Not completely. We received a small number of samples of the new transformer
but without manufacturing quantities we don't _know_ that it's solved. Only
something like 5% were failing in reflow so it's pretty hard to test three
samples for the problem. We have a very good manual test for the failure now
and an in-circuit test that tests ten out of fifteen of them. When we get
production quantities we can remove the manual test and will then rely on ICT
to flag any regression. Completely solved, no. We have a very good handle on
it and it's no longer impacting deliveries, so it's 95% of the way there.

From: Joerg on 27 Mar 2010 13:50
krw(a)att.bizzzzzzzzzzzz wrote:
> On Sat, 27 Mar 2010 08:54:26 -0700, Joerg <invalid(a)invalid.invalid> wrote:
>

[...]

>> Did you guys get the transformer issue licked?
>
> Not completely. We received a small number of samples of the new transformer
> but without manufacturing quantities we don't _know_ that it's solved. Only
> something like 5% were failing in reflow so it's pretty hard to test three
> samples for the problem. We have a very good manual test for the failure now
> and an in-circuit test that tests ten out of fifteen of them. When we get
> production quantities we can remove the manual test and will then rely on ICT
> to flag any regression. Completely solved, no. We have a very good handle on
> it and it's no longer impacting deliveries, so it's 95% of the way there.
>

If there is time you could cook two transformers. One from the old batch
and one of the new samples. Ratchet up the oven temp and see which one
is going at what temp. At least that'll tell you whetehr they really
used wire with better coating.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
From: krw on 27 Mar 2010 14:28
On Sat, 27 Mar 2010 10:50:32 -0700, Joerg <invalid(a)invalid.invalid> wrote:

>krw(a)att.bizzzzzzzzzzzz wrote:
>> On Sat, 27 Mar 2010 08:54:26 -0700, Joerg <invalid(a)invalid.invalid> wrote:
>>
>
>[...]
>
>>> Did you guys get the transformer issue licked?
>>
>> Not completely. We received a small number of samples of the new transformer
>> but without manufacturing quantities we don't _know_ that it's solved. Only
>> something like 5% were failing in reflow so it's pretty hard to test three
>> samples for the problem. We have a very good manual test for the failure now
>> and an in-circuit test that tests ten out of fifteen of them. When we get
>> production quantities we can remove the manual test and will then rely on ICT
>> to flag any regression. Completely solved, no. We have a very good handle on
>> it and it's no longer impacting deliveries, so it's 95% of the way there.
>>
>
>If there is time you could cook two transformers. One from the old batch
>and one of the new samples. Ratchet up the oven temp and see which one
>is going at what temp. At least that'll tell you whetehr they really
>used wire with better coating.

The "new" transformer only has the high temp wire on 1/2 of the primary, since
that's what is exposed. The transformers have a thermal time constant of
something like 8.5 minutes and are only baked for 3 minutes (about 10 seconds
at 250C, according to the profile). It's going to be real hard to balance
time and temperature to measure insulation melting with any confidence.
From: Joerg on 27 Mar 2010 14:31
krw(a)att.bizzzzzzzzzzzz wrote:
> On Sat, 27 Mar 2010 10:50:32 -0700, Joerg <invalid(a)invalid.invalid> wrote:
>
>> krw(a)att.bizzzzzzzzzzzz wrote:
>>> On Sat, 27 Mar 2010 08:54:26 -0700, Joerg <invalid(a)invalid.invalid> wrote:
>>>
>> [...]
>>
>>>> Did you guys get the transformer issue licked?
>>> Not completely. We received a small number of samples of the new transformer
>>> but without manufacturing quantities we don't _know_ that it's solved. Only
>>> something like 5% were failing in reflow so it's pretty hard to test three
>>> samples for the problem. We have a very good manual test for the failure now
>>> and an in-circuit test that tests ten out of fifteen of them. When we get
>>> production quantities we can remove the manual test and will then rely on ICT
>>> to flag any regression. Completely solved, no. We have a very good handle on
>>> it and it's no longer impacting deliveries, so it's 95% of the way there.
>>>
>> If there is time you could cook two transformers. One from the old batch
>> and one of the new samples. Ratchet up the oven temp and see which one
>> is going at what temp. At least that'll tell you whetehr they really
>> used wire with better coating.
>
> The "new" transformer only has the high temp wire on 1/2 of the primary, since
> that's what is exposed. The transformers have a thermal time constant of
> something like 8.5 minutes and are only baked for 3 minutes (about 10 seconds
> at 250C, according to the profile). It's going to be real hard to balance
> time and temperature to measure insulation melting with any confidence.


Then the only option would be to send them through the reflow oven "dry"
several times, together. Ratchet up the temp profile by 10C at a time
and see when the old one fails and when (or whether) the new one fails.
Of course if you have the SMT assy contracted out that isn't really
going to work.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
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