Sony SRF-M37V/W alignment


Gary DeBock
 

Hello Richard and Kevin,
 
     Because of a timing quirk, the SRF-M37V is one of the very few Ultralights that I haven't yet aligned.  It was part of the "Round One" Shootout posted on dxer.ca in late December, before I routinely started to align Ultralight radios prior to shootout competitions.  I know that local Puyallup, WA resident (and filter guru) Guy Atkins has done an alignment on an SRF-M37V, using instructions that I provided for a "quick and dirty" alignment on any AM portable without a service manual.  Perhaps he will read this, and share his experience. 
 
     For the benefit of those brave souls eager to align their Ultralight radio without a service manual, the "quick and dirty" alignment instructions are given below.  Proceed at your own risk, and be advised that some Ultralights (like the SRF-59) have a nasty reputation for inducing extreme regret in careless tinkerers.
 
1)  Remove the back cover to allow access to the loopstick.  Remove all wax binding the coil (or movable coil, if there are more than one) to the ferrite bar.  Ensure that the coil may be slid .25" either way, on the ferrite bar. NOTE:  The ICF-2010 and ICF-SW7600GR loopsticks cannot be aligned for sensitivity.
 
2)  If batteries are disconnected by the removal of the back panel, run jumpers and turn on the radio.  Tune in a WEAK station on the lower end of the dial (anything from 570- 630 kHz will do).  Slide the loopstick coil to peak the weak signal, and temporarily secure it with tape on the ferrite bar. NOTE:  This step will usually provide a major improvement in Ultralight radio sensitivity, and is quite easy to accomplish.
 
3)   Tune the radio to a WEAK station anywhere from 1360-1440 kHz.  On an analog radio, locate the 1400 kHz alignment trimmer (almost always located on the main tuning capacitor component) by attempting to peak the weak signal on the various trimmers, always after carefully noting the original position of the trimmers and returning to these exact positions, should the attempt prove unsuccessful.  The correct trimmer will peak the weak signal, but not shift the frequency to allow reception of adjacent stations.
    On a digital radio (assuming it is not the DT-200V, DT-200VX, DT-400W, DT-210V, DT-220V, E100, or C.Crane SWP for which we already have a procedure), the hobbyist will need to locate the correct 1400 kHz trimmer capacitor on the RF circuit board, usually adjacent to other trimmer capacitors for different bands.  Using the trial and error method described above for analog units, attempt to peak the weak signal by adjusting various trimmers, always after carefully noting the original position of the trimmers, and returning to these original positions if the peaking attempt is not successful.  The correct trimmer will peak the weak signal, but not shift the frequency to allow reception of adjacent stations.  NOTE:  AM IF transformers will behave exactly like 1400 kHz trimming capacitors, in peaking the weak signal. This is favorable to accomplish, since improvements in AM IF transformer peaking will increase the AM sensitivity.  For this reason, any component with an appearance like an IF transformer should have adjustment attempted, as described above.  The cumulative affect of multiple IF transformer adjustments can provide astonishing sensitivity improvements in some vintage radios like the TR-6400, 6R-33, etc.
 
4)   Return to the loopstick and attempt further peaking of the movable coil on the low-band (570- 630 kHz) weak signal by shifting the coil along the loopstick. If no further sensitivity improvement is noted, secure the coil in this position with wax, tape or a spot of woodworking glue. If a major improvement is noted, repeat Step 3, then repeat this step and secure the coil on the loopstick.
 
5)  Reassemble the radio, and enjoy the full sensitivity that the engineers designed for your particular model.
 
                             73,  Gary DeBock    
 
     
    




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bbwrwy
 

Has anyone performed an alignment of a M37? If so, could you share
with us how to do it?

Because I have three of these little receivers, I decided to
disassemble the least sensitive one. After removing four screws from
the back, you have to be careful with the clips holding the
logic/display circuit board in place. They are easily broken,
especially the one over the battery compartment. Also a short wire
runnig between the two circuit boards needs to be unsoldered. It's in
the lower left hand side, near the DX/local switch.

But I don't know where the adjustment points for alignment are
located. And I don't want to rely on guesswork.

I really enjoy using these little receivers, whether for general
listening or DXing. I always carry one (or a SRF-M35) with me to
sporting events. They fit into my hand just right and, in my opinion,
have a decent battery life. True, strong signals tend to spill over to
adjacent channels, such as local KFXY-1640 is heard from 1620 to 1660
kHz during the day. I assume this can be corrected somewhat with
tighter filters. So far I haven't found the images some others have
reported. However, I do wonder about Sony quality control because the
sensitivity on my three sets varies widely with the newer M37W being
the best. It's amazing how well the five centimeter antenna pulls in
signals. Its nulling ability is excellent.

The only real disappointment I've found is the weather band - it's
useless. I live in what is called "tornado alley" and the M37W's are
often sold locally (especially by Wal-Mart) as weather radios. It's
definitely false advertising.

Again, if anyone knows how to align the M37, please tell the rest of
us how it's done. It's a readily available, affordable ULR with DX
potential.


satya@...
 

Hi Richard:

Gary DeBock tried a couple places on-line who claimed to have M37V service
manuals, but no one ever actually sent him the manual. Not sure how much
he spent on the effort, but there appears to be no such manual readily
available. Now that Sony is coming out with the M37W model, perhaps Sony
will reissue the manual?

My M37V has weather band as well, and it appears to do fine picking up WB
here in the metro Seattle area. I haven't tried it out in a more distant
area, though.

73 - Kevin S
Bainbridge Island, WA

Has anyone performed an alignment of a M37? If so, could you share
with us how to do it?

Because I have three of these little receivers, I decided to
disassemble the least sensitive one. After removing four screws from
the back, you have to be careful with the clips holding the
logic/display circuit board in place. They are easily broken,
especially the one over the battery compartment. Also a short wire
runnig between the two circuit boards needs to be unsoldered. It's in
the lower left hand side, near the DX/local switch.

But I don't know where the adjustment points for alignment are
located. And I don't want to rely on guesswork.

I really enjoy using these little receivers, whether for general
listening or DXing. I always carry one (or a SRF-M35) with me to
sporting events. They fit into my hand just right and, in my opinion,
have a decent battery life. True, strong signals tend to spill over to
adjacent channels, such as local KFXY-1640 is heard from 1620 to 1660
kHz during the day. I assume this can be corrected somewhat with
tighter filters. So far I haven't found the images some others have
reported. However, I do wonder about Sony quality control because the
sensitivity on my three sets varies widely with the newer M37W being
the best. It's amazing how well the five centimeter antenna pulls in
signals. Its nulling ability is excellent.

The only real disappointment I've found is the weather band - it's
useless. I live in what is called "tornado alley" and the M37W's are
often sold locally (especially by Wal-Mart) as weather radios. It's
definitely false advertising.


bbwrwy
 

Thanks Kevin and Gary. I likewise tried, without success, to obtain a
service manual. As common as these receivers are you would think it'd
be easier. I feel the alignment process is fairly straight forward,
but I just don't want to do the wrong thing. The antenna detaches from
the bottom of the circuit board and it has two coils. I might send
along a photo or two for you to see.

Regarding the weather band, I can't hear any of the three NOAA
stations in area. All are within about 45 miles of my QTH. Of
course, I didn't buy the receivers to listen to NOAA. I simply wanted
a good receiver to stick in my pocket and it readily fits that
requirement.

Have a good DX weekend.

Richard Allen


bbwrwy
 

I've posted several photos of a disassembled SRF-M37V.

To get to the RF circuit board you need to unsolder the red wire in
the lower left hand corner must be unsoldered. When reassembling the
receiver resolder and fit it into the notch below the solder point.

Richard Allen.


Gary DeBock
 

Hi Guy, Richard and Kevin,
 
     The new SRF-M37W here needs to be aligned anyway before the Summertime Shootout, so I'll just put it at the top of the list, and write notes about which coils and trimmers to adjust.  For those needing alignment instructions for either the SRF-M37V or 37W models, this should do the trick.
 
     By the way, most of our current Ultralight model alignment instructions were made possible only by tinkerers performing "quick and dirty" operations without a service manual.  Guy was the first to perform the DT-200VX and SRF-T615 alignments, and deserves a lot of thanks for his efforts.  The E100 procedure was also developed this way here, among others.  The "quick and dirty" alignment procedure will also be performed on the SRF-M97V, SRF-S84, and DT-400W, before the Summertime Shootout.  We can then be sure how much sensitivity these units are capable of, as well as know how good the factory alignment is.
 
                                     73,  Gary
 
                                                                         
 
    




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Gary DeBock
 

Hello Richard,
 
     I just finished the MW alignment of my new SRF-M37W, in preparation for the Summertime Shootout.  It is not an alignment for the faint-hearted, to say the least.
 
     You were very close to finishing the alignment yourself--  the last step was to adjust the "CT2 MW RF" control to peak a high-band (1360-1450 kHz) weak signal.  This is the trimming capacitor closest to the upper right corner of the radio, and also the one at the tip of my index finger in a photo I will upload to the group photo site.
 
     The alignment itself requires a jumper wire between the disconnected red wire and the front circuit board ground, and also requires the hobbyist to hold the battery in place (to contact both the positive and negative leads).  In addition, the front panel should be placed over the front circuit board to allow use of the On-Off switch and Tuning controls, which creates quite a collection of jumpers, fingers, and circuit boards.
 
     The loopstick only has one coil secured with wax, however--  the other is secured with glue, and is not part of the 600 kHz alignment.  After this tricky procedure, no performance improvement was gained.  The new SRF-M37W was aligned to maximum sensitivity at the factory, with final sensitivity moderate in comparison to the SRF-T615.  Selectivity is still barn-door wide (local KSUH-1450 is heard from 1400-1610).
 
                                                                                 73,  Gary DeBock   
 

In a message dated 8/9/2008 7:00:42 P.M. Pacific Daylight Time, richarda@... writes:

Thanks everyone.

I managed to freed up the moving coil for the 600 kHz adjustment. Now
I need to figure out which control is used for the 1400 kHz
adjustment. My guess it's either the one marked "L4 MW OSC" or "CT2
MW RF". Because of thunderstorms I'll have to wait until another day.

I have to admit the E100 is easier to work on than the M37V/W. But as
some DXers have shown the little receiver has potential.

Richard Allen.

.


Guy Atkins
 

Hi Gary,
 
Unfortunately I have no useful information to share on the SRF-M37V alignment. This model was the very first one ultralight I tried to align, and in so doing I reduced the sensitivity somehow to a point where it only receives the strongest locals. In fact, I think I may have blown an input transistor or similar. I was careful to return all trimmers, inductors, etc. to their original settings but the sensitivity I ended up with is nowhere near the stock sensitivity.
 
I have had wonderful results with "quick and dirty" alignments on other models such as the Sangeans and Etons, but the M37V was a dismal failure. I have moved on to using other models, particularly the E100, and I don't plan to work further with the M37V.
 
73,
 
Guy Atkins
Puyallup, WA
 
 

-----Original Message-----
From: ultralightdx@... [mailto:ultralightdx@...]On Behalf Of D1028Gary@...
Sent: Friday, August 08, 2008 12:18 PM
To: ultralightdx@...
Subject: Re: [ultralightdx] Sony SRF-M37V/W alignment

Hello Richard and Kevin,
 
     Because of a timing quirk, the SRF-M37V is one of the very few Ultralights that I haven't yet aligned.  It was part of the "Round One" Shootout posted on dxer.ca in late December, before I routinely started to align Ultralight radios prior to shootout competitions.  I know that local Puyallup, WA resident (and filter guru) Guy Atkins has done an alignment on an SRF-M37V, using instructions that I provided for a "quick and dirty" alignment on any AM portable without a service manual.  Perhaps he will read this, and share his experience. 
 
 
   
.


bbwrwy
 

Thanks everyone.

I managed to freed up the moving coil for the 600 kHz adjustment. Now
I need to figure out which control is used for the 1400 kHz
adjustment. My guess it's either the one marked "L4 MW OSC" or "CT2
MW RF". Because of thunderstorms I'll have to wait until another day.

I have to admit the E100 is easier to work on than the M37V/W. But as
some DXers have shown the little receiver has potential.

Richard Allen.


bbwrwy
 

Thanks Gary:

I'd figured out everything but the CT2 adjustment. I give it a try on
another day.

Richard.