On Wednesday, March 4, 2015 at 8:40:58 PM UTC-6, WB wrote:

Plugged our Microair into a battery the wrong way 'round, did we? Been there, done that at least three times (yes, I am that stupid). The good news is that each time, it only cooked the picofuse and did no other damage.

The internal fuse (picofuse) is very easy to fix yourself. First you take out all 12,000 screws that hold the cover on. When you have the cover off, look for the picofuse in the top right rear corner of the radio (if I remember correctly). It looks a

lot like a resistor. It will be obviously burned if it is blown. It is a very common part, so your local electronic parts dealer should have them in stock. Clip the picofuse off by cutting the legs near the body of the fuse. This will make soldering on
the new fuse much easier. Solder the new fuse to the legs of the old fuse, bending it over a bit to make sure it is not sticking up in the way of the cover. Replace the cover with the 12,000 screws. Swing a dead cat over it, say "Arise" and your radio
should live again.

------------------------------------
Can anyone provide the specific pico-fuse and rating in order to repair a Microair 760 (post reverse polarity blowing it)? Indeed, I found where the fuse is soldered to the board as "WB" directed (tan/brown colored but with no other markings; circuit
board has "FB1" next to it [maybe "fastblow"?]). Pico-fuses are made by Littelfuse and there are many sources for ordering them, but not sure whether this one should be 1amp or 4A (the external fuse is 4A on the panel). Searched for a circuit diagram,
without success and the Microair manual provided no help and can't find a service manual. Is Aerotronics and/or Microairusa.com still servicing these units?
Thanks in advance,
Dee

--- SoupGate-Win32 v1.05
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On Sunday, July 9, 2023 at 2:23:16 PM UTC-4, Dee wrote:

On Wednesday, March 4, 2015 at 8:40:58 PM UTC-6, WB wrote:

Plugged our Microair into a battery the wrong way 'round, did we? Been there, done that at least three times (yes, I am that stupid). The good news is that each time, it only cooked the picofuse and did no other damage.

The internal fuse (picofuse) is very easy to fix yourself. First you take out all 12,000 screws that hold the cover on. When you have the cover off, look for the picofuse in the top right rear corner of the radio (if I remember correctly). It looks a

lot like a resistor. It will be obviously burned if it is blown. It is a very common part, so your local electronic parts dealer should have them in stock. Clip the picofuse off by cutting the legs near the body of the fuse. This will make soldering on
the new fuse much easier. Solder the new fuse to the legs of the old fuse, bending it over a bit to make sure it is not sticking up in the way of the cover. Replace the cover with the 12,000 screws. Swing a dead cat over it, say "Arise" and your radio
should live again.

------------------------------------
Can anyone provide the specific pico-fuse and rating in order to repair a Microair 760 (post reverse polarity blowing it)? Indeed, I found where the fuse is soldered to the board as "WB" directed (tan/brown colored but with no other markings; circuit

board has "FB1" next to it [maybe "fastblow"?]). Pico-fuses are made by Littelfuse and there are many sources for ordering them, but not sure whether this one should be 1amp or 4A (the external fuse is 4A on the panel). Searched for a circuit diagram,
without success and the Microair manual provided no help and can't find a service manual. Is Aerotronics and/or Microairusa.com still servicing these units?

Thanks in advance,
Dee

In the M760revQ manual, in the power paragraph (3.4) it says "...If reverse polarity is applied the internal fuse (4A) will blow." In the wiring diagram in the same manual, it shows an external 3A fuse as well.
If you search on PICO-Fuse - Digi-Key, it brings up a sheet with part numbers for various current ratings. It appears 275-004 (axial leads) or 276-004 (radial leads) would be your answer. There's a picture to show which looks most like your installation.
Have fun.

--- SoupGate-Win32 v1.05
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On Sunday, July 9, 2023 at 3:13:58 PM UTC-5, Dan Daly wrote:

On Sunday, July 9, 2023 at 2:23:16 PM UTC-4, Dee wrote:

On Wednesday, March 4, 2015 at 8:40:58 PM UTC-6, WB wrote:

Plugged our Microair into a battery the wrong way 'round, did we? Been there, done that at least three times (yes, I am that stupid). The good news is that each time, it only cooked the picofuse and did no other damage.

The internal fuse (picofuse) is very easy to fix yourself. First you take out all 12,000 screws that hold the cover on. When you have the cover off, look for the picofuse in the top right rear corner of the radio (if I remember correctly). It looks

a lot like a resistor. It will be obviously burned if it is blown. It is a very common part, so your local electronic parts dealer should have them in stock. Clip the picofuse off by cutting the legs near the body of the fuse. This will make soldering on
the new fuse much easier. Solder the new fuse to the legs of the old fuse, bending it over a bit to make sure it is not sticking up in the way of the cover. Replace the cover with the 12,000 screws. Swing a dead cat over it, say "Arise" and your radio
should live again.

------------------------------------
Can anyone provide the specific pico-fuse and rating in order to repair a Microair 760 (post reverse polarity blowing it)? Indeed, I found where the fuse is soldered to the board as "WB" directed (tan/brown colored but with no other markings; circuit

board has "FB1" next to it [maybe "fastblow"?]). Pico-fuses are made by Littelfuse and there are many sources for ordering them, but not sure whether this one should be 1amp or 4A (the external fuse is 4A on the panel). Searched for a circuit diagram,
without success and the Microair manual provided no help and can't find a service manual. Is Aerotronics and/or Microairusa.com still servicing these units?

Thanks in advance,
Dee

In the M760revQ manual, in the power paragraph (3.4) it says "...If reverse polarity is applied the internal fuse (4A) will blow." In the wiring diagram in the same manual, it shows an external 3A fuse as well.
If you search on PICO-Fuse - Digi-Key, it brings up a sheet with part numbers for various current ratings. It appears 275-004 (axial leads) or 276-004 (radial leads) would be your answer. There's a picture to show which looks most like your

installation.

Have fun.

Thank you, Dan!
Dee

--- SoupGate-Win32 v1.05
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On Monday, July 10, 2023 at 12:20:18 PM UTC-4, Dee wrote:

On Sunday, July 9, 2023 at 3:13:58 PM UTC-5, Dan Daly wrote:

On Sunday, July 9, 2023 at 2:23:16 PM UTC-4, Dee wrote:

On Wednesday, March 4, 2015 at 8:40:58 PM UTC-6, WB wrote:

Plugged our Microair into a battery the wrong way 'round, did we? Been there, done that at least three times (yes, I am that stupid). The good news is that each time, it only cooked the picofuse and did no other damage.

The internal fuse (picofuse) is very easy to fix yourself. First you take out all 12,000 screws that hold the cover on. When you have the cover off, look for the picofuse in the top right rear corner of the radio (if I remember correctly). It

looks a lot like a resistor. It will be obviously burned if it is blown. It is a very common part, so your local electronic parts dealer should have them in stock. Clip the picofuse off by cutting the legs near the body of the fuse. This will make
soldering on the new fuse much easier. Solder the new fuse to the legs of the old fuse, bending it over a bit to make sure it is not sticking up in the way of the cover. Replace the cover with the 12,000 screws. Swing a dead cat over it, say "Arise" and
your radio should live again.

------------------------------------
Can anyone provide the specific pico-fuse and rating in order to repair a Microair 760 (post reverse polarity blowing it)? Indeed, I found where the fuse is soldered to the board as "WB" directed (tan/brown colored but with no other markings;

circuit board has "FB1" next to it [maybe "fastblow"?]). Pico-fuses are made by Littelfuse and there are many sources for ordering them, but not sure whether this one should be 1amp or 4A (the external fuse is 4A on the panel). Searched for a circuit
diagram, without success and the Microair manual provided no help and can't find a service manual. Is Aerotronics and/or Microairusa.com still servicing these units?

Thanks in advance,
Dee

In the M760revQ manual, in the power paragraph (3.4) it says "...If reverse
polarity is applied the internal fuse (4A) will blow." In the wiring diagram in the same manual, it shows an external 3A fuse as well.
If you search on PICO-Fuse - Digi-Key, it brings up a sheet with part numbers for various current ratings. It appears 275-004 (axial leads) or 276-004 (radial leads) would be your answer. There's a picture to show which looks most like your

installation.

Have fun.

Thank you, Dan!
Dee

Replace the internal 4 amp fuse and then swap out the external panel fuse for a 3 amp as per the manual. Then, the next time you blow a fuse it will the the external one that goes, not the internal one.

--- SoupGate-Win32 v1.05
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On Monday, July 10, 2023 at 5:44:03 PM UTC-5, stephen.s...@gmail.com wrote:

On Monday, July 10, 2023 at 12:20:18 PM UTC-4, Dee wrote:

On Sunday, July 9, 2023 at 3:13:58 PM UTC-5, Dan Daly wrote:

On Sunday, July 9, 2023 at 2:23:16 PM UTC-4, Dee wrote:

On Wednesday, March 4, 2015 at 8:40:58 PM UTC-6, WB wrote:

Plugged our Microair into a battery the wrong way 'round, did we? Been there, done that at least three times (yes, I am that stupid). The good news is that each time, it only cooked the picofuse and did no other damage.

The internal fuse (picofuse) is very easy to fix yourself. First you take out all 12,000 screws that hold the cover on. When you have the cover off, look for the picofuse in the top right rear corner of the radio (if I remember correctly). It

looks a lot like a resistor. It will be obviously burned if it is blown. It is a very common part, so your local electronic parts dealer should have them in stock. Clip the picofuse off by cutting the legs near the body of the fuse. This will make
soldering on the new fuse much easier. Solder the new fuse to the legs of the old fuse, bending it over a bit to make sure it is not sticking up in the way of the cover. Replace the cover with the 12,000 screws. Swing a dead cat over it, say "Arise" and
your radio should live again.

------------------------------------
Can anyone provide the specific pico-fuse and rating in order to repair a Microair 760 (post reverse polarity blowing it)? Indeed, I found where the fuse is soldered to the board as "WB" directed (tan/brown colored but with no other markings;

circuit board has "FB1" next to it [maybe "fastblow"?]). Pico-fuses are made by Littelfuse and there are many sources for ordering them, but not sure whether this one should be 1amp or 4A (the external fuse is 4A on the panel). Searched for a circuit
diagram, without success and the Microair manual provided no help and can't find a service manual. Is Aerotronics and/or Microairusa.com still servicing these units?

Thanks in advance,
Dee

In the M760revQ manual, in the power paragraph (3.4) it says "...If reverse
polarity is applied the internal fuse (4A) will blow." In the wiring diagram in the same manual, it shows an external 3A fuse as well.
If you search on PICO-Fuse - Digi-Key, it brings up a sheet with part numbers for various current ratings. It appears 275-004 (axial leads) or 276-004 (radial leads) would be your answer. There's a picture to show which looks most like your

installation.

Have fun.

Thank you, Dan!
Dee

Replace the internal 4 amp fuse and then swap out the external panel fuse for a 3 amp as per the manual. Then, the next time you blow a fuse it will the the external one that goes, not the internal one.

Stephen,
That sounds like solid advice and would save the trouble of opening the case to solder another one in. I'm assuming that idea can be bench-tested by wiring the 2 fuses in series to see which one blows first once the current flows (via a dummy circuit)?
Thanks,
Dee

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 11/07/2023 03:18, Dee wrote:

On Monday, July 10, 2023 at 5:44:03 PM UTC-5, stephen.s...@gmail.com wrote:

On Monday, July 10, 2023 at 12:20:18 PM UTC-4, Dee wrote:

On Sunday, July 9, 2023 at 3:13:58 PM UTC-5, Dan Daly wrote:

On Sunday, July 9, 2023 at 2:23:16 PM UTC-4, Dee wrote:

On Wednesday, March 4, 2015 at 8:40:58 PM UTC-6, WB wrote:

Plugged our Microair into a battery the wrong way 'round, did we? Been there, done that at least three times (yes, I am that stupid). The good news is that each time, it only cooked the picofuse and did no other damage.

The internal fuse (picofuse) is very easy to fix yourself. First you take out all 12,000 screws that hold the cover on. When you have the cover off, look for the picofuse in the top right rear corner of the radio (if I remember correctly). It

looks a lot like a resistor. It will be obviously burned if it is blown. It is a very common part, so your local electronic parts dealer should have them in stock. Clip the picofuse off by cutting the legs near the body of the fuse. This will make
soldering on the new fuse much easier. Solder the new fuse to the legs of the old fuse, bending it over a bit to make sure it is not sticking up in the way of the cover. Replace the cover with the 12,000 screws. Swing a dead cat over it, say "Arise" and
your radio should live again.

------------------------------------
Can anyone provide the specific pico-fuse and rating in order to repair a Microair 760 (post reverse polarity blowing it)? Indeed, I found where the fuse is soldered to the board as "WB" directed (tan/brown colored but with no other markings;

circuit board has "FB1" next to it [maybe "fastblow"?]). Pico-fuses are made by Littelfuse and there are many sources for ordering them, but not sure whether this one should be 1amp or 4A (the external fuse is 4A on the panel). Searched for a circuit
diagram, without success and the Microair manual provided no help and can't find a service manual. Is Aerotronics and/or Microairusa.com still servicing these units?

Thanks in advance,
Dee

In the M760revQ manual, in the power paragraph (3.4) it says "...If reverse
polarity is applied the internal fuse (4A) will blow." In the wiring diagram in the same manual, it shows an external 3A fuse as well.
If you search on PICO-Fuse - Digi-Key, it brings up a sheet with part numbers for various current ratings. It appears 275-004 (axial leads) or 276-004 (radial leads) would be your answer. There's a picture to show which looks most like your

installation.

Have fun.

Thank you, Dan!
Dee

Replace the internal 4 amp fuse and then swap out the external panel fuse for a 3 amp as per the manual. Then, the next time you blow a fuse it will the the external one that goes, not the internal one.

Stephen,
That sounds like solid advice and would save the trouble of opening the case to solder another one in. I'm assuming that idea can be bench-tested by wiring the 2 fuses in series to see which one blows first once the current flows (via a dummy circuit)?
Thanks,
Dee

Do not just consider the Fuse Ampere rating, but if it is Fast(F) or
(FF) or Delay/Slow-Blow. Age can also have an effect.

Don't know for sure about MicroAir, but I would guess that there is a Back-Biased diode across the input, to blow the fuse in the event of Reverse-Polarity rather than allow damage to the radio.

Be Warned:Reverse-Polarity can damage the diode, so that it will not
protect you again.

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Been here, done that. Wasn't too difficult.

The 4A picofuse is available from Amazon for $3 for 10ea (a lifetime supply). You can try eBay also.
https://www.amazon.com/10pcs-Littelfuse-Pico-Fuse-Voltage/dp/B07V1JQHK9

It appears that there is a US repair shop for the MicroAir760 http://www.microairusa.com/
But it helpfully states, "We are an independent repair facility with long wait times."

PS - I don't have a schematic to determine if a diode is in the power input circuit to blow the fuse. But it may have survived as it could probably handle the very short term amp surge until the fuse blew.

--- SoupGate-Win32 v1.05
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