blowing ULN2803C on LPF-Control

D Solt · 2025-03-13T08:31:38-07:00

I have blown two U10's during receiver calibration this week. This is after operating for several hours. One popped when calibrating the 10m band and one when calibrating 6m. A nice puff of smoke is

blowing ULN2803C on LPF-Control

D Solt All Messages By This Member #6158 I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds
Albert Peter All Messages By This Member #6159 开云体育 Dave, Specifically which U10 went on which board. We have multiple ICs with the same designation. Could you also give a run down of your configuration? V12 boards from what source, etc?? Al toggle quoted message Show quoted text From: [email protected] <[email protected]> on behalf of D Solt via groups.io <davesolt@...> Sent: Wednesday, March 12, 2025 4:13 PM To: [email protected] <[email protected]> Subject: [AmateurRadioBuilders] blowing ULN2803C on LPF-Control ? I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds
K9HZ All Messages By This Member #6160 开云体育 Something is not right. There is nothing connected to those parts that would cause a short great enough to cause smoke. ?Its a ULN2803 that drives the relays (open collector to ground when activated). ?Somehow those open collectors of the part must be fed by 12V WITHOUT the relay coil as a resistance. ?? Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email:??bill@... ? toggle quoted message Show quoted text On Mar 12, 2025, at 1:13?PM, D Solt via groups.io <davesolt@...> wrote: ? I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds
K9HZ All Messages By This Member #6161 开云体育 Ohhhh wait. ?Make sure the cable (low control J27) pins 2 and 4 are not somehow switched to 7 and 9 by being 180 degrees wrong !!! That would cause this. ? 12V directly on the OCL!!! Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email:??bill@... ? toggle quoted message Show quoted text On Mar 12, 2025, at 1:13?PM, D Solt via groups.io <davesolt@...> wrote: ? I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds
K9HZ All Messages By This Member #6163 开云体育 More data here… look what happens if you spin the cable connected to J24 around 180 degrees…. you have the 12V+ from pins 2 & 4 NOW on pins 7 & 9 (the 10M and the 6M lines), BUT THEY go to U10 and are OPEN COLLECTOR to GROUND.? So then… when you select EITHER 10M or 6M you BLOW UP U10… ? ? ? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? toggle quoted message Show quoted text From: [email protected] <[email protected]> On Behalf Of K9HZ Sent: Wednesday, March 12, 2025 4:11 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] blowing ULN2803C on LPF-Control ? Ohhhh wait. ?Make sure the cable (low control J27) pins 2 and 4 are not somehow switched to 7 and 9 by being 180 degrees wrong !!! That would cause this. ? 12V directly on the OCL!!! ? Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: ? email:??bill@... ? On Mar 12, 2025, at 1:13?PM, D Solt via groups.io <davesolt@...> wrote: ? I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds
D Solt All Messages By This Member #6166 开云体育 ULN2803 on the LPF Control board. I found the problem. The high filter ribbon cable was inverted from what it should be. Embarrassing mistake.? dave toggle quoted message Show quoted text On Mar 12, 2025, at 4:40?PM, Albert Peter via groups.io <albertfpeter@...> wrote: ? Dave, Specifically which U10 went on which board. We have multiple ICs with the same designation. Could you also give a run down of your configuration? V12 boards from what source, etc?? Al From: [email protected] <[email protected]> on behalf of D Solt via groups.io <davesolt@...> Sent: Wednesday, March 12, 2025 4:13 PM To: [email protected] <[email protected]> Subject: [AmateurRadioBuilders] blowing ULN2803C on LPF-Control ? I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds
D Solt All Messages By This Member #6167 开云体育 Thanks Bill. The cable was inverted.? dave toggle quoted message Show quoted text On Mar 12, 2025, at 5:10?PM, K9HZ via groups.io <bill@...> wrote: ?Ohhhh wait. ?Make sure the cable (low control J27) pins 2 and 4 are not somehow switched to 7 and 9 by being 180 degrees wrong !!! That would cause this. ? 12V directly on the OCL!!! Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email:??bill@... ? On Mar 12, 2025, at 1:13?PM, D Solt via groups.io <davesolt@...> wrote: ? I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds
K9HZ All Messages By This Member #6168 开云体育 Perfect! ? Or not so much, but its fixed now! Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email:??bill@... ? toggle quoted message Show quoted text On Mar 12, 2025, at 6:47?PM, D Solt via groups.io <davesolt@...> wrote: ?Thanks Bill. The cable was inverted.? dave On Mar 12, 2025, at 5:10?PM, K9HZ via groups.io <bill@...> wrote: ?Ohhhh wait. ?Make sure the cable (low control J27) pins 2 and 4 are not somehow switched to 7 and 9 by being 180 degrees wrong !!! That would cause this. ? 12V directly on the OCL!!! Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email:??bill@... ? On Mar 12, 2025, at 1:13?PM, D Solt via groups.io <davesolt@...> wrote: ? I have blown two U10's during receiver calibration this week.? This is after operating for several hours.? One popped when calibrating the 10m band and one when calibrating 6m.? A nice puff of smoke is generated.? Any thoughts on why this may be happening? dave, n3ds

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