Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 12:32 am
Page 3 of 7
Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 1:29 am
The MRF186, I would set it at 100W - it’s always best to under run them a little. The MRF9180 (if you get lucky and the gates don’t pop) run it no more than 150W, preferably 130 to 140, the difference in field strength will be unnoticeable.
Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 12:18 pm
Does anyone happen to have the pcb files for these amps?I know there are ones for 7£ on Ebay but that seems a bit steep when I could get 10 of them knocked out for 7£ from china.
Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 1:30 pm
I copied the original PCB and modified it somewhat, I’ll post up the files tomorrow. However with the price of these kits being so cheap out of China it’s probably cheaper to negotiate a bulk purchase from the Chinese vendor.
Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 3:03 pm
OK but some of these fake ones don't give out full power.Electronically wrote: ↑Sun Apr 12, 2020 10:23 pm If there fake and work it does the job. It's just basically a copy of the original.
I got these 3 from Aliexpress @ €9.19 each - Seller: AIICKING Store
They only produced 20W RF output. My Pic
Another Aliexpress buyer had the same problem. Note the production number under MRF9180 are the same > RR1627E
So... these are definitely a bad batch
I replaced the MRF9180 with a genuine one in November 2019, it's been running at 26V @ 8A for 16hrs a day at a reasonable temperature ever since.Electronically wrote: ↑Sun Apr 12, 2020 10:23 pm Reason these copy's or originals don't last long is because most folk crank up the Volts to make it go at boiling point.
Re: RE: Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 3:14 pm
Brian I don't believe you have been running these 16 hours a dayBriansBrain wrote:OK but some of these fake ones don't give out full power.Electronically wrote: ↑Sun Apr 12, 2020 10:23 pm If there fake and work it does the job. It's just basically a copy of the original.
I got these 3 from Aliexpress @ €9.19 each - Seller: AIICKING Store
They only produced 20W RF output. My Pic
Another Aliexpress buyer had the same problem. Note the production number under MRF9180 are the same > RR1627E
So... these are definitely a bad batch
I replaced the MRF9180 with a genuine one in November 2019, it's been running at 26V @ 8A for 16hrs a day at a reasonable temperature ever since.Electronically wrote: ↑Sun Apr 12, 2020 10:23 pm Reason these copy's or originals don't last long is because most folk crank up the Volts to make it go at boiling point.
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Re: RE: Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 3:39 pm
Actually it's 16 hours and +/- 15 minutes a dayElectronically wrote: ↑Mon Apr 13, 2020 3:14 pm Brian I don't believe you have been running these 16 hours a day
Every day I get up at 7:45 first I have a pee
Then go into Brian's Studio / Workshop and turn all his computers on
,Then I go up one floor to Brian's RF rack which is in the little roof house.
So Brian's RF gear gets turned on about 7:52
Then...
Every night I select a slow track for his last tune of the day to play after the BBC news at Midnight.
Then trundle up the stairs once again and turn the RF rack OFF
At +/- 12:08
Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 3:49 pm
@BriansBrain do you sprinke magic dust on the gates of the FET before you set the bias?
Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 6:15 pm
Nah... but I don't set the bias using a Voltage reading
I was given instructions from an old friend of mine that was big in the pirate radio game in Merseyside back in the 80's
This is what he told me...
I have actually set mine to a quiescent board current for a total of around 225mA When Cold +/- 21C°If your board has a pre set pot to adjust the quiescent current then connect the supply voltage
Under no RF drive conditions adjust the drain quiescent current for a total of around 300mA.
This device is a dual FET so 150mA per drain.
This is a good starting point for class B biasing and depending on your input drive and how it is coupled
to the gate you will need to experiment with the bias current, i wouldn't go much over 400mA total though.
Connect your power meter in line with a well matched load and you are looking for a max power of around
180W, I wouldn't go much above that as the class B biasing will return an efficiency of around 78%.
Don't try and push the device for maximum ratings.
If you are trying to squeeze 200W from the device then any miss-matches could send the device over the edge.
Hope this is of help mate but there is no one answer, it always involved a little experimentation.
As I have found when the MRF9180 is HOT the quiescent board current without ant RF drive is around 400mA
He also told me, if it says 26V Max on the data sheet then it will be OK at 26V
I drive the 150W linear using one of these boards from ebay it has an adjustable power output. Every morning I turn the 150W linear on with No RF Drive and I see +/- 220mA on the current meter on the front of the amp.
then turn up the little 15W linear until the 150W linear reaches 8A then it's set for the day.
Re: RE: Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 7:48 pm
Brian see all those transistors you've shown.my question is why have you got 3 genuine chips that you have used are they all blown? .BriansBrain wrote:OK but some of these fake ones don't give out full power.Electronically wrote: ↑Sun Apr 12, 2020 10:23 pm If there fake and work it does the job. It's just basically a copy of the original.
I got these 3 from Aliexpress @ €9.19 each - Seller: AIICKING Store
They only produced 20W RF output. My Pic
Another Aliexpress buyer had the same problem. Note the production number under MRF9180 are the same > RR1627E
So... these are definitely a bad batch
I replaced the MRF9180 with a genuine one in November 2019, it's been running at 26V @ 8A for 16hrs a day at a reasonable temperature ever since.Electronically wrote: ↑Sun Apr 12, 2020 10:23 pm Reason these copy's or originals don't last long is because most folk crank up the Volts to make it go at boiling point.
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Re: RE: Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 9:05 pm
The one in the pics are not genuine chipsElectronically wrote: ↑Mon Apr 13, 2020 7:48 pm Brian see all those transistors you've shown.my question is why have you got 3 genuine chips that you have used are they all blown? .
Those three in the picture I got from Aliexpress @ €9.19 each - Seller: AIICKING Store
That only produced 20W RF output are obviously Fakes... and bad ones at that
They are not blown just useless at only 20W output
Look here >>> viewtopic.php?f=11&t=2373
Re: RE: Re: RE: Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Mon Apr 13, 2020 9:17 pm
Lol I was tricking you to see if you would slip up with the fake to genuine ones. OK so it's official they Aliexpress chips are only doing 20 Watts. I've never tried Aliexpress chips to be honest.BriansBrain wrote:The one in the pics are not genuine chipsElectronically wrote: ↑Mon Apr 13, 2020 7:48 pm Brian see all those transistors you've shown.my question is why have you got 3 genuine chips that you have used are they all blown? .
Those three in the picture I got from Aliexpress @ €9.19 each - Seller: AIICKING Store
That only produced 20W RF output are obviously Fakes... and bad ones at that
They are not blown just useless at only 20W output
Look here >>> viewtopic.php?f=11&t=2373
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Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 2:35 am
MRF9180 is best (in the boards I've used) at 21V with just over 2.2W of drive for 135 Watts out. Efficiency is in the 70% - 75% range. IIn the early days, I steamed a couple of them to over 200 Watts, but they died pretty quickly (despite being genuine ones). I messed with them a lot in the Chinese cheap boards and found the 21V / 135W to be about the most reliable point.
The MRF186 is OK at 90 Watts into a horrible load (a blown-down aerial!).
The MRF186 is OK at 90 Watts into a horrible load (a blown-down aerial!).
Re: RE: Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 7:11 am
Albert your absolutely correct on this 21volts is best. Any higher it will damage.Albert H wrote:MRF9180 is best (in the boards I've used) at 21V with just over 2.2W of drive for 135 Watts out. Efficiency is in the 70% - 75% range. IIn the early days, I steamed a couple of them to over 200 Watts, but they died pretty quickly (despite being genuine ones). I messed with them a lot in the Chinese cheap boards and found the 21V / 135W to be about the most reliable point.
The MRF186 is OK at 90 Watts into a horrible load (a blown-down aerial!).
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Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 8:32 am
First the driver that you use ia not stable and can easy generate spurr and only working "clean"on full power
This little amp will produce 15W if you only put your finger in the input of the amp
Maybe this is the problem
i have had many 9180 on the workbench and all working day after day
Also a other thing can be static from you antenna...
Why not buying a good amp and stay away of the china boards?
I see that you use the 15W driver but what is your output of the PLL osc?
This little amp will produce 15W if you only put your finger in the input of the amp
Maybe this is the problem
i have had many 9180 on the workbench and all working day after day
Also a other thing can be static from you antenna...
Why not buying a good amp and stay away of the china boards?
I see that you use the 15W driver but what is your output of the PLL osc?
Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 10:35 am
Maybe he has changed it to the RD06HVF1.RF-Head wrote: ↑Tue Apr 14, 2020 8:32 am First the driver that you use ia not stable and can easy generate spurr and only working "clean"on full power
This little amp will produce 15W if you only put your finger in the input of the amp
Maybe this is the problem
i have had many 9180 on the workbench and all working day after day
Also a other thing can be static from you antenna...
Why not buying a good amp and stay away of the china boards?
I see that you use the 15W driver but what is your output of the PLL osc?
Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 11:17 am
BriansBrain wrote: ↑Mon Apr 13, 2020 6:15 pmNah... but I don't set the bias using a Voltage reading
I was given instructions from an old friend of mine that was big in the pirate radio game in Merseyside back in the 80's
This is what he told me...I have actually set mine to a quiescent board current for a total of around 225mA When Cold +/- 21C°If your board has a pre set pot to adjust the quiescent current then connect the supply voltage
Under no RF drive conditions adjust the drain quiescent current for a total of around 300mA.
This device is a dual FET so 150mA per drain.
This is a good starting point for class B biasing and depending on your input drive and how it is coupled
to the gate you will need to experiment with the bias current, i wouldn't go much over 400mA total though.
As I have found when the MRF9180 is HOT the quiescent board current without ant RF drive is around 400mA
He also told me, if it says 26V Max on the data sheet then it will be OK at 26V
Idq of a 9180 is 1400mA
Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 11:44 am
could be to do with the ft of 880Mhzronald001 wrote: ↑Tue Apr 14, 2020 11:17 amBriansBrain wrote: ↑Mon Apr 13, 2020 6:15 pmNah... but I don't set the bias using a Voltage reading
I was given instructions from an old friend of mine that was big in the pirate radio game in Merseyside back in the 80's
This is what he told me...I have actually set mine to a quiescent board current for a total of around 225mA When Cold +/- 21C°If your board has a pre set pot to adjust the quiescent current then connect the supply voltage
Under no RF drive conditions adjust the drain quiescent current for a total of around 300mA.
This device is a dual FET so 150mA per drain.
This is a good starting point for class B biasing and depending on your input drive and how it is coupled
to the gate you will need to experiment with the bias current, i wouldn't go much over 400mA total though.
As I have found when the MRF9180 is HOT the quiescent board current without ant RF drive is around 400mA
He also told me, if it says 26V Max on the data sheet then it will be OK at 26V
Idq of a 9180 is 1400mA
Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 12:32 pm
Well I use that board because of the variable RF output, it is stable, and does not produce spurr at low powerRF-Head wrote: ↑Tue Apr 14, 2020 8:32 am First the driver that you use ia not stable and can easy generate spurr and only working "clean"on full power
This little amp will produce 15W if you only put your finger in the input of the amp
Maybe this is the problem
i have had many 9180 on the workbench and all working day after day
Also a other thing can be static from you antenna...
Why not buying a good amp and stay away of the china boards?
I see that you use the 15W driver but what is your output of the PLL osc?
I only use it at low power to drive the MRF9180 board
I drive that with 15W a Tugicom TX180 1W exciter... I drive the Tugicom at MPX from Breakaway Broadcast 0.90.69
I don't have a problem....
My system is working @ 150w 16hrs a day...
every day It's the original poster of this thread has the problem
Re: Mrf9180 Keeps blowing!!
Posted: Tue Apr 14, 2020 12:38 pm
Nope I use Genuine RD15HVF1 and I have not had any problems with it.teckniqs wrote: ↑Tue Apr 14, 2020 10:35 amMaybe he has changed it to the RD06HVF1.RF-Head wrote: ↑Tue Apr 14, 2020 8:32 am First the driver that you use ia not stable and can easy generate spurr and only working "clean"on full power
This little amp will produce 15W if you only put your finger in the input of the amp
Maybe this is the problem
i have had many 9180 on the workbench and all working day after day
Also a other thing can be static from you antenna...
Why not buying a good amp and stay away of the china boards?
I see that you use the 15W driver but what is your output of the PLL osc?
Mind you I only use this boards at low power for it's variable output capability