Topics

Went Dead

Bill Watkins
 

Replaced both IRF510 with lead-free version.  Used insulator kit.  Installed fan.  Did PA bias. Up and running again. Thanks for all suggestions. 

Bill
K0WHW

Bill Watkins
 

Thank you 

Bill Watkins
 

Thank you 

Roy Appleton
 

Thank you very much for the information!

Roy
WA0YMH

On Sat, Jun 16, 2018, 1:21 PM Ralph Mowery <rmowery42@...> wrote:
This should be a link to my Google drive where you can see some pix.  With the RD16HHF1  if you lay the tab down on a table with the leads facing you , you have to cross the two leads on the right of both transistors so they will match the holes in the original ubitx .  You could use the original transistors but they would have to be insulated from the heat sink.  This ubitx has been modified in several ways and the output transformer was changed. 


I was lucky in that the box I found to put it in was just the size to cut a hole in the front for the display and in the back for the heat sink.  It was an old Bud box I picked up at a hamfest a while back that someone had started a project but never finished. 

I found the heat sink on ebay from China for about $ 5 shipped.  It was about 6 inches long, but I cut it to about 4 inches 


73 de ku4pt



On Sat, Jun 16, 2018 at 12:47 PM, Roy Appleton <twelveoclockhigh@...> wrote:
I'd love to see a close up of the new finals, crossed leads and heat sink if you could!

Roy
WA0YMH

Ralph Mowery
 

The V4 board is the latest ubitx circuit board.  It has several modifications to it from the original ubitx circuit board.  One of the main ones is the audio IC was replaced by several transistors as there seems to be a real quality control problem with the original IC.  

Mr. Farhan is looking at all the mods that have been made by others and using some of the best of them in the V4 boards.

While the original works very well for the price there have been lots of modifications to it and the software.  I think he did a great job of making the original by keeping the price very low.  While I can not do much with the engineering of the electronics, I have enjoyed making some of the modifications to the ubitx.  I look at this as the way I am at chess.  I know how each piece moves, but when playing with a real chess player I get beat in about 3 moves because I don't know how to hook it all together.

The IRF510 can be mounted by using the insulators.  I don't know much about the IRF510 but the RD16HHF is a 'real' RF device and the specs say it will withstand a SWR of about 20 :1 .  However it is about $ 10 per pair instead of the $ 1 a pair for the IRDF510s.

de ku4pt


On Sat, Jun 16, 2018 at 3:09 PM, Bill Watkins <kf7yxs@...> wrote:
What’s a V4 board, and since I’ve already ordered the 510,  that will be what I have for awhile.  


On Jun 16, 2018, at 14:00, ajparent1/KB1GMX <kb1gmx@...> wrote:

The V4 board solves the crossover problem.  

The RD16HHF is a device people have used and its a good part but its also 10$ for a pair 
from reputable sources.  Apply the mods suggested by the users of that part for best result.

As to mounting the original IRF510 there are insulator kits and silicon based heat transfer
grease that its the time tested solution.

Allison
_

ajparent1/KB1GMX
 

The QCX is a very different beast from the uBitx.

The QCX uses a class E final the expects the transistor to act very much like a switch.
The advantage is extremely high efficiency over 85% its typical or higher and very
little power expended in the device. The need is the device must switch fast and hard
and IRF510 and RD parts while they can do this need much more energy into the
gate to do it.  The reward is if done well a single IRF510 will do 30-40W at 12V, however
its not a drop in thing.  These are typically monoband designs.  This works well for
CW, AM, and other constant carrier modes.

The uBitx uses a series of linear amp stages that include the finals.  At best efficiency of
each stage may be 55% or lower with a fair amount of power and heat expended.
This is a requirement for undistorted SSB and multiband designs.

What applies to QCX and uBitx are very different.

Allison

Bill Watkins
 

What’s a V4 board, and since I’ve already ordered the 510,  that will be what I have for awhile.  


On Jun 16, 2018, at 14:00, ajparent1/KB1GMX <kb1gmx@...> wrote:

The V4 board solves the crossover problem.  

The RD16HHF is a device people have used and its a good part but its also 10$ for a pair 
from reputable sources.  Apply the mods suggested by the users of that part for best result.

As to mounting the original IRF510 there are insulator kits and silicon based heat transfer
grease that its the time tested solution.

Allison

ajparent1/KB1GMX
 

The V4 board solves the crossover problem.  

The RD16HHF is a device people have used and its a good part but its also 10$ for a pair 
from reputable sources.  Apply the mods suggested by the users of that part for best result.

As to mounting the original IRF510 there are insulator kits and silicon based heat transfer
grease that its the time tested solution.

Allison

Bill Watkins
 

Very interesting and clever.  Thanks for the tip.  How closely are the RD16HHF1 equivalent to the original mosfet?  I do like being able to bolt the heat sink to the case and use the case which is already ground to handle some heat and secure things.  Like you say, not a possibility with the original mosfet.


Bill



On Jun 16, 2018, at 11:21 AM, Ralph Mowery <rmowery42@...> wrote:

This should be a link to my Google drive where you can see some pix.  With the RD16HHF1  if you lay the tab down on a table with the leads facing you , you have to cross the two leads on the right of both transistors so they will match the holes in the original ubitx .  You could use the original transistors but they would have to be insulated from the heat sink.  This ubitx has been modified in several ways and the output transformer was changed. 


I was lucky in that the box I found to put it in was just the size to cut a hole in the front for the display and in the back for the heat sink.  It was an old Bud box I picked up at a hamfest a while back that someone had started a project but never finished. 

I found the heat sink on ebay from China for about $ 5 shipped.  It was about 6 inches long, but I cut it to about 4 inches 


73 de ku4pt



On Sat, Jun 16, 2018 at 12:47 PM, Roy Appleton <twelveoclockhigh@...> wrote:
I'd love to see a close up of the new finals, crossed leads and heat sink if you could!

Roy
WA0YMH


Ralph Mowery
 

This should be a link to my Google drive where you can see some pix.  With the RD16HHF1  if you lay the tab down on a table with the leads facing you , you have to cross the two leads on the right of both transistors so they will match the holes in the original ubitx .  You could use the original transistors but they would have to be insulated from the heat sink.  This ubitx has been modified in several ways and the output transformer was changed. 


I was lucky in that the box I found to put it in was just the size to cut a hole in the front for the display and in the back for the heat sink.  It was an old Bud box I picked up at a hamfest a while back that someone had started a project but never finished. 

I found the heat sink on ebay from China for about $ 5 shipped.  It was about 6 inches long, but I cut it to about 4 inches 


73 de ku4pt



On Sat, Jun 16, 2018 at 12:47 PM, Roy Appleton <twelveoclockhigh@...> wrote:
I'd love to see a close up of the new finals, crossed leads and heat sink if you could!

Roy
WA0YMH

Roy Appleton
 

I'd love to see a close up of the new finals, crossed leads and heat sink if you could!

Roy
WA0YMH


On Sat, Jun 16, 2018, 11:36 AM Ralph Mowery <rmowery42@...> wrote:
While they cost close to $ 5 each  you may want to look at replacing the outputs with some RD16HHF1.  One good thing is the tab is at ground so you can bolt it directly to a heat sink.  You will have to cross two of the leads as the pinout is slightly different.  I did this and put a very large heat sink on mine to handle the extra heat from doing other mods to get the power up on some of the bands.

de ku4pt


On Sat, Jun 16, 2018 at 12:09 PM, Bill Watkins <kf7yxs@...> wrote:
Absolutely right about using a new plan and your’s and other’s suggestions!

Have to think through the new heat sink . .  Maybe leave wspr to qrp labs qcx for now; purposely built for that.  I have a qrp labs US3 on the bench. Those two will do all the wspr I need. I’ll leave the ubitx for cw and phone. 

 Have to get it transmitting again first.  Will definitely pay attention to the list guidance for replacing the mosfet. 

Was definitely good feeling to have that qrp chat on it right out of the box. Really like this radio. Fan already installed in the new enclosure. It’s a computer type; probably not enough. 

Bill




On Jun 16, 2018, at 08:40, Doug W <dougwilner@...> wrote:

If you are using WSJT-X for WSPR there is a tx% setting.  At 100% it sends every time cycle, lower less.  I still wouldn't tx WSPR without a plan to remove the heat but a lower tx% will also give the MOSFETS a much needed break.

If you need some tips for removing the IRF510's from the board search this list it happens often enough.
--
www.bitxmap.com


Ralph Mowery
 

While they cost close to $ 5 each  you may want to look at replacing the outputs with some RD16HHF1.  One good thing is the tab is at ground so you can bolt it directly to a heat sink.  You will have to cross two of the leads as the pinout is slightly different.  I did this and put a very large heat sink on mine to handle the extra heat from doing other mods to get the power up on some of the bands.

de ku4pt


On Sat, Jun 16, 2018 at 12:09 PM, Bill Watkins <kf7yxs@...> wrote:
Absolutely right about using a new plan and your’s and other’s suggestions!

Have to think through the new heat sink . .  Maybe leave wspr to qrp labs qcx for now; purposely built for that.  I have a qrp labs US3 on the bench. Those two will do all the wspr I need. I’ll leave the ubitx for cw and phone. 

 Have to get it transmitting again first.  Will definitely pay attention to the list guidance for replacing the mosfet. 

Was definitely good feeling to have that qrp chat on it right out of the box. Really like this radio. Fan already installed in the new enclosure. It’s a computer type; probably not enough. 

Bill




On Jun 16, 2018, at 08:40, Doug W <dougwilner@...> wrote:

If you are using WSJT-X for WSPR there is a tx% setting.  At 100% it sends every time cycle, lower less.  I still wouldn't tx WSPR without a plan to remove the heat but a lower tx% will also give the MOSFETS a much needed break.

If you need some tips for removing the IRF510's from the board search this list it happens often enough.
--
www.bitxmap.com


Bill Watkins
 

Absolutely right about using a new plan and your’s and other’s suggestions!

Have to think through the new heat sink . .  Maybe leave wspr to qrp labs qcx for now; purposely built for that.  I have a qrp labs US3 on the bench. Those two will do all the wspr I need. I’ll leave the ubitx for cw and phone. 

 Have to get it transmitting again first.  Will definitely pay attention to the list guidance for replacing the mosfet. 

Was definitely good feeling to have that qrp chat on it right out of the box. Really like this radio. Fan already installed in the new enclosure. It’s a computer type; probably not enough. 

Bill




On Jun 16, 2018, at 08:40, Doug W <dougwilner@...> wrote:

If you are using WSJT-X for WSPR there is a tx% setting.  At 100% it sends every time cycle, lower less.  I still wouldn't tx WSPR without a plan to remove the heat but a lower tx% will also give the MOSFETS a much needed break.

If you need some tips for removing the IRF510's from the board search this list it happens often enough.
--
www.bitxmap.com

Doug W
 

If you are using WSJT-X for WSPR there is a tx% setting.  At 100% it sends every time cycle, lower less.  I still wouldn't tx WSPR without a plan to remove the heat but a lower tx% will also give the MOSFETS a much needed break.

If you need some tips for removing the IRF510's from the board search this list it happens often enough.
--
www.bitxmap.com

Bill Watkins
 

It never crossed my mind because I made wrong assumptioms..   I have qrp lab's qrx on 30 meters that runs 24/7, every 30 minutes on wspr. That runs on bs170. 

I'm learning. 



Sent via the Samsung Galaxy Tab E, an AT&T 4G LTE tablet

-------- Original message --------
From: Philip <philip.g7jur@...>
Date: 6/15/18 16:34 (GMT-06:00)
To: BITX20@groups.io
Subject: Re: [BITX20] Went Dead

Transmitting WSPR will run the PA flat out for 2 minutes, with the standard heatsinks I am not surprised they blew.
I run a small fan near the heatsinks. 

Philip G7JUR

Philip
 

Transmitting WSPR will run the PA flat out for 2 minutes, with the standard heatsinks I am not surprised they blew.
I run a small fan near the heatsinks. 

Philip G7JUR

Bill Watkins
 

Thanks to All!! 

The Radio is on the shelf, a fuse holder and several irf510(s) are ordered, and my other radio is up to bat. lol.

Good lessons learned about replacing displays, re-working arduino code, and mosfets.  Fun times, actually.  

Wish local store carried the mosfet . . . .

73,

Bill
K0WHW


  

On Jun 15, 2018, at 1:31 PM, ajparent1/KB1GMX <kb1gmx@...> wrote:

Bill,

The list is not a direct replacement list each has differences.

If you replace the failed device replace both with the same vendors IRF510.
(BUY TWO).  IF they charge more than 1.50$ each its robbery.

When you replace them you must reset Bias.  NExt time whats the temperatures.

Allison

ajparent1/KB1GMX
 

Bill,

The list is not a direct replacement list each has differences.

If you replace the failed device replace both with the same vendors IRF510.
(BUY TWO).  IF they charge more than 1.50$ each its robbery.

When you replace them you must reset Bias.  NExt time whats the temperatures.

Allison

Bill Watkins
 

I was in middle of a wspr transmission. Had done several within the hour. Possibly didn’t wait long enough for pa to cool. I don’t know. 

Had contact on 20 with good signal report earlier.  Radio was working. 

Arv Evans
 

Just replacing the IRF-510 devices may not be enough.  Something caused the failure.  Was it
an intermittent antenna connection that drove SWR too high?  Or was it a power spike that
punched through the MOSFET structure?
Finding and fixing the cause might be the first order of business, before replacing the damaged
components.

Arv  K7HKL
_._


On Fri, Jun 15, 2018 at 1:43 PM Clark Martin <kk6isp@...> wrote:
With the symptoms described there is a microscopic chance it’s something other than a shorted MOSFET.  You might want to consider replacing both final transistors.  Whatever killed the one that is shorted may have damaged the other.  Make sure to buy several spares, this may not be the first time you need to replace them.

I’d strongly suggest putting a fuse inline, this may protect the final transistors from future damage and also protect your power source from overload if it does happen again.

Make sure you replace the thermal grease between the transistors and heatsink.  Don’t forget to set the bias adjustment for the new transistor (you should probably verify the bias adjustment for the other.

Below are some reputable sources for replacement IRF510s:

https://www.mouser.com/ProductDetail/Vishay-Siliconix/IRF510PBF?qs=sGAEpiMZZMshyDBzk1%2fWi1F3z9PgzPBnjAas2zQPJco%3d


https://www.jameco.com/z/IRF510-Major-Brands-Transistor-IRF510-MOSFET-N-Channel-100-Volt_209234.html?CID=GOOG&gclid=EAIaIQobChMI7cCJuLTW2wIVEsNkCh3wXQNhEAkYASABEgLGAfD_BwE

https://www.arrow.com/en/products/irf510pbf/vishay?utm_source=google&utm_campaign=g-shp-us-fet_transistors&utm_medium=cpc&utm_term=PRODUCT+GROUP&gclid=EAIaIQobChMItr2Vt7TW2wIVQ41-Ch1L7gdWEAkYASABEgLXDfD_BwE&gclsrc=aw.ds&dclid=CIaN0ti01tsCFUzLZAodA5cAUg

https://www.alliedelec.com/vishay-pcs-irf510pbf/70078850/?mkwid=s6sX9YbUa&pcrid=30980760979&gclid=EAIaIQobChMItr2Vt7TW2wIVQ41-Ch1L7gdWEAkYBCABEgKC6PD_BwE

http://www.newark.com/vishay/irf510pbf/n-channel-mosfet-100v-5-6a-to/dp/63J7301?mckv=sNl2veeHe_dc%7Cpcrid%7C81515566701%7Cplid%7C%7Ckword%7C%7Cmatch%7C%7Cslid%7C%7Cproduct%7C63J7301%7C&gross_price=true&CATCI=pla-148794670821&CAAGID=20376568701&CMP=KNC-GUSA-GEN-SHOPPING-63J7301&CAGPSPN=pla&gclid=EAIaIQobChMItr2Vt7TW2wIVQ41-Ch1L7gdWEAkYBiABEgK82_D_BwE&CAWELAID=120185550001121418

Clark Martin
KK6ISP

> On Jun 15, 2018, at 12:24 PM, Bill Watkins <kf7yxs@...> wrote:
>
> Thanks,
>
> So, one mosfet is shorted.  I'm no electronics wiz so I have to ask basic questions.  It's an irf510, right?  Fry's electronics shows no item of that name.  Is there another company that makes something generically the same, or is there a similar item available at Fry's that I can replace it with?
>
> Is that the real issue?  With the zero ohms from source to drain on one transistor and with the unit powering up when brown wire disconnected is shorted mosfet the answer to this problem (at least short-term, anyway)?