HL2 receiver issues (very low -60db?) - repair? or sell for parts?

[Don Hobson]

GE,

Hope everyone is well and safe.

Well....I guess I should not have bragged so much on this little HL2 jewel as I finally had some time off work today to actually not just listen on voice but tried some voice QSO's today (previous QSOs short on FT8 or PSK or CW...using small FL110 amp round 35-40w out or so).  Contacts on 17m and 40m voice no issues...went to 20m and all of a sudden middle of transmit with QSO my transmit stopped and the receive went to almost nothing.  Using Mosley33 and SWR 1.2 never any issues...other rigs all fine....the HL2 also fine on transmit once rebooted (normal 5 to 6 watts), hear the filters work as normal when switching bands so no issues (normal 10 over 9 signals now at 1 or less and tonight even normal strong 30 over signals at max of s2...doesn't appear to be any software setting that I can find but something within the HL2).

Anyone have any suggestions what to look for or if anyone repairs these?  Or just sell for parts or as is but it does work yet but just very very low receive (the receive was impressive prior).

Thanks for any replies (prior you all have been very helpful with my questions on the HL2 and software and all...and appreciate that).

Don KB9UMT 

stay safe

[Steve Haynal]

Hi Don,

Please check if the RX LNA is still functional. Connect to a dummy load or no antenna and adjust the LNA gain in Quisk. Do you see the noise floor level vary? (Some software adjusts the noise floor calculation based on the LNA setting, but Quisk doesn't and allows you to see the effects of the LNA.)

Try some finger pressure on U7, T2 and other components in the RX path. Is there any sensitive component which causes the RX gain to come back? You can find the schematic at www.hermeslite.com to see what is on the RX path.

If you have a soldering iron or hot air, try reflowing U7. I've seen cases where this brings back the LNA. If you don't feel comfortable working on a SMT component, at least make sure that the hidden pad accessed by a hole underneath U7 on the back of the PCB is well soldered. You can use a regular soldering iron for this although it can take some time to heat everything up.

When and where did your purchase the board? It may still qualify for a repair or exchange. You can always send the board to me for repair. If it is something simple it is just the cost of $7.50 for a small flat rate package. Replacing U7 or U2 can cost anywhere from $75 to $150 as I use another company for that work.

73,

Steve

kf7o

[Don Hobson]

Hi Steve kf7o,

Thanks so much for the reply.

Answer to your first question on RX LNA and if I see the noise floor level vary.....answer is YES.

Answer to your 2nd question on finger pressure on U7, T2 and other components to see if RX gain comes back....answer is NO.

U7 appears ok from what I can see (my eyes not so good on this small board).

Answer to your 3rd question.....bought this HL2 used about month or two ago from a nice Op out on the East Coast (the board shows a date on it of 2019, not sure if that helps or if there are any other numbers on the board that would help you determine anything). \

I will most likely ship it out to you and take you up on your kind offer to take a look if that is okay, do you need the money to ship back in the box when mailing or can I pay with PayPal+fee for any costs?.......and I assume you are good on QRZ.com for mailing address.

Thanks

Don KB9UMT

Don KB9UMT 

[Robert McKinley]

I see this is an old thread but I have the exact same symptoms with my HL2. What was the resolution? I suspect the TVS diode D1.

[Steve Haynal]

The TR relay was bad in this case. After replacing it the HL2 worked fine.

73,

Steve

kf7o

[radi...@mail.com]

I feel sure there is a whole thread (or more) about replacing the T/R relay somewhere on here? Or was that relays on the N2ADR board? Sorry, no time to look, but possibly a common cause of this issue? I've occasionally seen similar on my HL2 but always managed to clear it by a few rapid cycles of the TX/RX mode. Recently seems to have gone away.

73

Max

[Jiri Culak]

Hello all

as you might remember my original first HL2 was blown by close in RF (clamping protection diode, 8:1 transformer...all that went including the relay in N2ADR LPF Board..... well, that is when you run 1kW on 80m and leave 160m TX antenna plugged into ANT Port.... (one relay failed which meant to prevent this....)

Anyway long story short - I have ordered 4 pieces of AD9866BCZP I believe and got myself better hot air SMD Rework station. I spend many attempts and three ICs with very little success - I thought maybe FPGA was fried too?But then IP Stack was running....so I dropped in last AD9866 and suddenly , I dont have RX (most of time...will get to that) but I do have TX/RX switching, I have a solid TX and I have an RX when I either put my finger very close to output of AD9866, where it feeds data to FPGA. I checked and all connections are there, it seems like if somehow capacity of my body preevents oscilation or spurs on data stream to FPGA?? Very interesting.

So question to group or perhaps Steve - are there any blocking CAPs or ferrite beads which could have been damaged and I should check for?

BR Jiri OK2IT 

Dne neděle 12. března 2023 v 11:01:34 UTC+1 uživatel radi...@mail.com napsal:

[Steve Haynal]

Hi Jiri,

It is often possible to mistake a SMD solder joint as good when it is bad. Have you inspected with a microscope?

Where did you get the AD9866BCZP parts? From AliExpress? In the beginning I ordered AD9866 from AliExpress. Zel Pro installed some for me but informed me that most were cracked or had other damage, often hard to spot. 

In your situation, I would use a signal generator connected to the HL2 and use an oscilloscope to check all points on the RX path to the AD9866 include the AD9866 pins. I could compare that to a known good HL2. I can't point to any specific part in the chain which may be bad. Other pins on the AD9866 matter for RX too, so I would ensure all connections are well soldered.

73,

Steve

kf7o