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Went Dead

 

Was in middle of wspr transmission. Radio went dark. Power source checks out good. When cycle off and on, display just slightly flashes. Display and raduino work fine with usb to computer.

What happened? Where do I start?

Bill
 

Something has shorted. take out the PA power line and check?

- f

On Fri, Jun 15, 2018 at 11:54 AM, Bill Watkins <kf7yxs@...> wrote:
Was in middle of wspr transmission. Radio went dark. Power source checks out good. When cycle off and on, display just slightly flashes. Display and raduino work fine with usb to computer.

What happened?? Where do I start?

Bill
 

开云体育

Is there a troubleshooting guide with suggested voltages and resistance? ?

Probing what I believe to be collector and emitter on the two IRF510, looking from the rear, the left shows no flow from collector to emitter, ?but the right shows 37.4 from collector to emitter.

Forgive me if using wrong terms. ?New learning experience.



On Jun 14, 2018, at 11:28 PM, Ashhar Farhan <farhanbox@...> wrote:

Something has shorted. take out the PA power line and check?

- f

On Fri, Jun 15, 2018 at 11:54 AM, Bill Watkins <kf7yxs@...> wrote:
Was in middle of wspr transmission. Radio went dark. Power source checks out good. When cycle off and on, display just slightly flashes. Display and raduino work fine with usb to computer.

What happened?? Where do I start?

Bill
 

They are mosfets and do not have have collector or emitter.

It looks like your probing Drain to Source and one way should be nesr open and the other
you should see the substrate diode.

IF the fets are shorted then will show near zero ohms Source to Drain.?

When you turn it on how many amps does it require?
What is the Voltage at the power supply after you turn it on?
If you disconnect the BROWN wire (power to the output transistors) does it power up?

Allison
 

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Did the quickest check first. When brown wire disconnected, it powers up.?

Btw, I appreciate your help very much.?

Bill
K0WHW




On Jun 15, 2018, at 12:06, ajparent1/KB1GMX <kb1gmx@...> wrote:

They are mosfets and do not have have collector or emitter.

It looks like your probing Drain to Source and one way should be nesr open and the other
you should see the substrate diode.

IF the fets are shorted then will show near zero ohms Source to Drain.?

When you turn it on how many amps does it require?
What is the Voltage at the power supply after you turn it on?
If you disconnect the BROWN wire (power to the output transistors) does it power up?

Allison

 

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)?

Bill
K0WHW
 

开云体育

Wondering about complimentary/equivalence???

image1.png


On Jun 15, 2018, at 14:24, 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)?

Bill
K0WHW
 

Hi Bill,

Mouser has them under a dollar. Buy a couple of spares and ask them ship them via usps (lower cost first class postage). So far I haven't fried mine :)

73,

Bill KU8H

On 06/15/2018 03:24 PM, Bill Watkins 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)?

Bill
K0WHW
--
bark less - wag more
 

I bought some spares from Mouser very easily.

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

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:












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)?
 

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:












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)?
 

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.?
 

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
 

开云体育

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

 

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
 

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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)
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

 

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.
--

 

开云体育

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.
--

 

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.
--


 

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.
--


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