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I have a bit too much experience with cooking the finals on my ubitx...I'm on about my fourth or fifth set of IRF510s.? I think that I'm probably overdriving too much on digital modes...but here's the question
After the last replacement and re-biasing of the PAs using the standard +100 mA per pot technique, I found that I had decent power on 40m, but had virtually no output on 20m or 17m (where I'd previously seen at least a few watts out).
so...here's my question: did I perhaps damage something other than the irf510s, or do I perhaps have bad irf510s (these were from a different batch)?? I have an oscilloscope and a dvm, but not really 100% sure how to proceed.? I had an idea that I might want to put on a dummy load, use the wsjt-x 'tune' function (with a relatively low drive setting) and then measure at different points, but I'm fairly new to electronics and not sure enough what I'd be looking for. I was thinking perhaps checking each amplification stage, but would need some advice on what to look for.
Ideas???
Thanks!
Sean
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Did you replace both?
Did any traces top side or bottom side heat up or disappear.
Scoping stages has been what I consider the least useful step.
Look for smoked parts.
Allison
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I replaced both, yes. First time I have replaced with “international rectifier” marked parts from asia, which is why I was wondering if that may be it.
Have been looking for visibly cooked bits in the amplifier section, but so far no joy...will continue though ?
thanks
Sean
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Look like you are ended to fake IRF510 from china
On Fri, Aug 17, 2018 at 8:47 AM, Sean W7SKD <sean.jrdalys@...> wrote: I replaced both, yes. First time I have replaced with “international rectifier” marked parts from asia, which is why I was wondering if that may be it.
Have been looking for visibly cooked bits in the amplifier section, but so far no joy...will continue though ?
thanks
Sean
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On Thu, Aug 16, 2018 at 11:17 PM, Sean W7SKD wrote:
First time I have replaced with “international rectifier” marked parts from asia, which is why I was wondering if that may be it.
I'll put $10 on that :-\ 73, Mark.
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Praba jee ?Mark? could be right ?if some one buys RD16 devices, ?perhaps faking is possible?? like using IRF and we know that. ?But irf 510 perhaps no one need fake them. all the best
sarma ?vu3zmv
On Fri, Aug 17, 2018 at 8:51 AM Mark McNabb < n7eku@...> wrote: On Thu, Aug 16, 2018 at 11:17 PM, Sean W7SKD wrote:
First time I have replaced with “international rectifier” marked parts from asia, which is why I was wondering if that may be it.
I'll put $10 on that :-\
73,
Mark.
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I guess this image says it all. Experience and image courtsey Sandeep Lohia VU3SXT.
Rahul VU3WJM
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Yes that’s probably true. ?Had had a few fakes components. ?Just because it label as something it’s actually something else.
But it waste your life trying to fault find something that isn’t real. ?Frustrating ?
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On 17 Aug 2018, at 1:40 pm, Mvs Sarma < mvssarma@...> wrote: Praba jee ?Mark? could be right ?if some one buys RD16 devices, ?perhaps faking is possible?? like using IRF and we know that. ?But irf 510 perhaps no one need fake them. all the best
sarma ?vu3zmv
On Fri, Aug 17, 2018 at 8:51 AM Mark McNabb < n7eku@...> wrote: On Thu, Aug 16, 2018 at 11:17 PM, Sean W7SKD wrote:
First time I have replaced with “international rectifier” marked parts from asia, which is why I was wondering if that may be it.
I'll put $10 on that :-\
73,
Mark.
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Here’s how this ended up going: ?I saw no damage to any traces, no damage to any components really. I replaced the IR marked irf510s (sourced from Tayda) with Vishay Silconix marked irf510s (from Arrow) and everything is back to normal functioning. I don’t know if the IR parts were actually “bad” but they were certainly different.? Pics of of the parts below - Vishay on the left? 
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Here's a clue:
International Rectifier gave up on building IRF510's years ago.
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On Fri, Aug 17, 2018 at 08:57 PM, Sean W7SKD wrote:
Here’s how this ended up going: ?I saw no damage to any traces, no damage to any components really. I replaced the IR marked irf510s (sourced from Tayda) with Vishay Silconix marked irf510s (from Arrow) and everything is back to normal functioning. I don’t know if the IR parts were actually “bad” but they were certainly different.?
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It would be nice to know what is and is not good from Tayda as they have low prices and low cost shipping.guress sometimes you git what you pay for...
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I suspect those so-called IRF510's from Tayda are good enough if you plan to use them for their intended purpose.
Specifically, for use as low speed power switches.
To use an IRF510 at 10 or 20 mhz means it had better meet all the specs of the original part.
You want parts from a reputable top line vendor (Arrow, Mouser, Digikey, etc).
from a reputable manufacturer (these days that would be from Vishay).
?
Tayda is in the business of cutting costs on this stuff.
That means using clones.
And the clones sometime don't meet exactly the same spec's as the original parts.
The clones generally work, but not always.
Quality control can be less than ideal.
For example, there are reports of Nano clones that mostly work
but suck 4x the power that they should.
Or have a bad ADC input.?
I have bought stuff from Tayda, and have been happy with what I got.
But Tayda, at those prices, is not shipping the same stuff you would get from Mouser.
I would not consider buying RF semiconductors from other than first tier vendors.
Way more trouble than it's worth getting an RF amp to work with bad parts.
Can be trouble enough when using known good parts.?
Jerry
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On Sat, Aug 18, 2018 at 07:17 AM, ohwenzelph wrote:
It would be nice to know what is and is not good from Tayda as they have low prices and low cost shipping.guress sometimes you git what you pay for...
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But.....IRF510 devices have not been made for International Rectifier for over 20 years.
They licensed the die to a South Korean firm, who had them manufactured in China.
Not sure where the Bulgarian (Vishay) devices are coming from.? 8-)
Arv
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On Sat, Aug 18, 2018 at 8:59 AM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: I suspect those so-called IRF510's from Tayda are good enough if you plan to use them for their intended purpose.
Specifically, for use as low speed power switches.
To use an IRF510 at 10 or 20 mhz means it had better meet all the specs of the original part.
You want parts from a reputable top line vendor (Arrow, Mouser, Digikey, etc).
from a reputable manufacturer (these days that would be from Vishay).
?
Tayda is in the business of cutting costs on this stuff.
That means using clones.
And the clones sometime don't meet exactly the same spec's as the original parts.
The clones generally work, but not always.
Quality control can be less than ideal.
For example, there are reports of Nano clones that mostly work
but suck 4x the power that they should.
Or have a bad ADC input.?
I have bought stuff from Tayda, and have been happy with what I got.
But Tayda, at those prices, is not shipping the same stuff you would get from Mouser.
I would not consider buying RF semiconductors from other than first tier vendors.
Way more trouble than it's worth getting an RF amp to work with bad parts.
Can be trouble enough when using known good parts.?
Jerry
On Sat, Aug 18, 2018 at 07:17 AM, ohwenzelph wrote:
It would be nice to know what is and is not good from Tayda as they have low prices and low cost shipping.guress sometimes you git what you pay for...
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International Rectifier originated the IRF510 back in the 1970's or so,
but have long since given up building them.
Other reputable manufacturers have been Fairchild, Harris, and Siliconix.
I think Siliconix is now part of Vishay.
The reputable vendors seem to be mostly selling Vishay branded IR510's these days.
The Vishay parts are slightly different than the old IR parts,
Some marginal amp designs that had been fiddled with till they worked
when using the IR parts did not work with the Vishay parts.
But generally, and in the case of the *Bitx* rigs specifically, the Vishay parts work fine.
I have no idea where Tayda get's their "IR IRF510".
I suspect there is very little connection with International Rectifier.
Radio Shack used to sell a bad clone of the IRF510 called the IFR510.
At least they were (somewhat) honest about it.
Caused a lot of confusion.
Jerry
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On Sat, Aug 18, 2018 at 09:12 AM, Arv Evans wrote:
But.....IRF510 devices have not been made for International Rectifier for over 20 years.
They licensed the die to a South Korean firm, who had them manufactured in China.
Not sure where the Bulgarian (Vishay) devices are coming from.? 8-)
Arv
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IR became part of Infineon and Silconix is part of Vishay.
The Vishay parts are likely Silconix foundry.
Better than even bet there was more damage than fried finals.
What is hard for me to understand is why cook them to death?
Allison
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Jerry,
Tayda is an unknown to me.
Its pretty hard to make a show MOSFET.? However many circuits are very sensitive
due to poor design to the high gate capacitance of some MOSFETS.
Every time I got IRF510s from friends claimed to be bogus they were either good
and the unit under repair was a mess or they were indeed bad ,as in blown.
Blown?? Yes, lest we forget these are MOSFETS the gate is susceptible to ESD
from packaging and handling.? Every bad one I've tested had very high gate leakage
suggesting damage.
MOSFETs not wrapped in anti-static material or with the leads shorted are to be viewed
as suspect till proven good.? They are very rugged but tempting the fates is foolish.
Allison
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Here's a thread and a quote for part of it, that I found on the web about them,
Quality of Tada parts is always an issue. I may speak for the developers and PCB suppliers present here that build a lot of prototypes and most of us had issues with diodes, JFETs and Op Amps from Tayda where the prototyping failedbecause of these parts.
The only things I buy from them are the Alpha pots as they are still ok.
LEDs have been ok but not the RGB types.
You can also buy resistors and caps but dont expect the values you order. Always meassure them.
I you look close you see that the leads are very thin compared to parts sourced from other sources.
MLCC caps are ok but not really cheap. Electrolytics are ok too but you need to check the meassurements in the datasheet -if they have one. They are usually not the smallest
Milled IC sockets are ok. Pin headers not, they are hard to solder in.
Do not expect to see the same parts when ordering now and 4weeks later.
You can but standard OpAmps or Digital ICs like TL072 or CD40106 but nothing that is usually very expensive from other sources. You will get what you pay for? 
If I need high quality parts in a short time I use Mouser but ai will order in quantities and therefore they are cheap for me.
I have a local electronics online store here in Germany for small orders- but compared to Mouser their shipping rates piss me off more if you look at the numbers you get and the shipping you pay for.
Nichicon is a good source for small electrolytic caps.
73, Mark
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Stay away from their 1/8" phone plugs. I had the tip of one fall off inside a jack. Problem was the jack was on the back of my Kenwood TS430 and I had to pull the back panel to get the jack out to get that piece out. After looking closer at the other ones I have, they're all loose - even the new ones in the drawer.
Vince - K8ZW.
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On 08/18/2018 10:17 AM, ohwenzelph via Groups.Io wrote:
It would be nice to know what is and is not good from Tayda as they have
low prices and low cost shipping.guress sometimes you git what you pay
for...
--
Michigan VHF Corp.
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