The AM Forum

http://electronicdesign.com/article/embedded/what_electronics_gear_have_you_repaired_lately.aspx?nl=1

I'll stick to the thru-hole PCBs and stuff I can see.
I work on Kenwood commercial two-way radios (handhelds and mobiles) and the stuff is beginning to get really tiny. The boss will not spend any money on a macro-focus video cam and a hot air soldering station, so we send the "can't get to that component problem" to another shop for those repairs.
There are YouTube teardowns of cell phones to "unlock" them and test jig set-ups to open the phone to other SIM cards and I was surprised how many layers of crap there is in a cell phome.
For those who have vision and steady hands....more power to YOU!!
SMT stuff is on the hairy edge of my abilities now.
Fred

SMT is quite easy but what the heck do you do with BGA

I'm not a gadget nut so I don't have anything with the latest large iPad chips, that I have to have working.  Outside of the shack, I guess I depend on my mac mini, DSL modem, answering machine and cordless phone and DTV converter box.  Everything else is relatively old technology.  If any of the above quit on me I'd probably simply junk it, (except for the mac mini--that cost too much) and buy another one.  I can work on surface mount if I have to but I really don't like it.  My time and priorities are on keeping the important gear (ham gear) working and thankfully, it is all older technology except for some of the audio processing boxes, and I am gradually moving to older analog gear with them too.  I want to eventually be able to do all my own repairs.

This is one of the reasons why I hesitate to get into the modern DSP ham gear--the flex radio type stuff--how do you fix it when it breaks?

When it got beyond repairing at the discrete component level that's where it passed me by.  Most of my stuff is point-to-point wired.

I did do my share of circuit board work in the 70's and 80's when I did field service work and later, commercial VHF and UHF two-way, but if the PCB doesn't have little holes in it with wires poked through I don't bother.

I had to do BGA junk at Datalux. Intel chipsets required it. They had some good tools for it. All PACE, Inc. stuff, where I worked in the mid 80's.

Awaiting on the Retro 75 now paper work has been mailed. :)

73

Jack.

A 1967 all solid state stereo receiver/amp.    I built a new stereo demodulator board using a phase-locked-loop type IC to replace the crummy original board.    Also blew out an audio driver transistor in the power amp, while trying to trouble shoot a noisy PA channel.     I fixed the driver, but the amp is still noisy.    One thing I failed to fix was a Kenwood 2M handheld.    I found that the audio output surface mount power amp was bad.    Tried to replace it,  was not successful and added it to the junk pile.    No more attempts fixing anything surface mount.

Some have been successful in repairing laptops and PCs whose BGA chips have bad connections by putting the board in the oven for a few minutes.

The last thing I fixed was my wifes auto nite light. It needed a new light bulb.  ;D

I used to do SMT stuff.  I can't see close up any more so I don't touch it.  Furthermore, to me it's not worth trouble. Going to RS to find a replacement SMT resistor or cap ain't happenin'.

Fixed the oldest Daughter's rear windshield wiper motor, actually it was
the PB Blaster that did the job I was the Finger man. :)

73

Jack.

I have worked on and built many PC boards over the years, but I'm not very fond of SMT stuff.  Take a look at cellphones, PCs, etc. That stuff is all assembled with automation.  Really difficult to replace anything on a component level.  I am most comfortable with old tube-type junk.  Still fairly easy to work on, although I did just complete the little Small Wonder Labs Retro 75 AM Transceiver board and it went pretty well.  Nice PC board with plated-thru holes for components.  It is really a challenge, however,  to read values on those tiny components.  Get out the magnifying glass! 

73,  Jack, W9GT

JN,
Do you add flux or just heat?
We XRAY them here at work but not sure if they do touch up.

HQ-140XA, stereo receiver, 4-channel amplifier, Swan 250C

It wasn't surface mount but several years ago I repaired the digital display in my TS-820S with a heat gun.  I followed all of the Kenwood service notes correcting problems with the plated through connections and looked at everything under a microscope but still no happiness.  After spending the better part of a weekend with no positive results out of frustration I used a heat gun to reflow the solder and it has now been working fine for over 5 years.  I do NOT recommend this procedure since generally anger and frustration leads to bad outcomes but this case was an exception.

Recent repairs include a pair of Swan 600 twins, a Johnson Viking Invader 200, a Hallicrafters SX-9, and I have a Lafayette Professional 9 receiver on the bench now. 

I definitely prefer working on the earlier stuff and I strongly prefer radio work to other electronics.  This morning I was going out to spray Roundup and the the garage door opened half way and stopped due to a stripped gear in the opener.  I remembered that I had installed this garage door opener 12 years ago after the control card in the previous opener gave up the ghost after only a couple of years.  I transplanted the control card from the stripped gear unit into the other one and 90 minutes later I had a working garage door and I could finally start spraying.  Just as I finished with the herbicide UPS dropped off the Sears parts (nylon dogs) to repair my washing machine so now after repairing a garage door opener, spraying 20 gallons of Roundup, repairing a washing machine, and taking a much needed shower I can spend some more time with my new Lafayette receiver.

About the last 10 years of my working career I spent considerable R&D time under a microscope working mostly RX/TX millimeter wave up to 75 gHz. Linear amp packages get mighty small up there. When the last company got sold, downsized and shipped a lot of work to CA and Mexico I bought a B&L microscope and quite a bit of hi end test equipment at fire sale prices. Kept what I wanted and sold the rest to wind up with a good total profit.

The last 30 days Ive overhauled for myself or customers a SX-28, SX-17 (mine), HRO-500, NC-240D (shipped me 3, 2 more to go), two NCL-2000's, Henry 8K, and converted to 6M a SB-221, LK-450, and LK-500. Backlog looks similar for the next month and beyond.

And I still get a little time for antenna work and waste my time here :P  ::)

Gotta find more junk at Nearfest 8)

Carl
KM1H

Well, let's see. I've been working on the Siltronix 90-6 VFO that was the subject of an earlier thread on this forum, modifying a Motorola amplified speaker that I picked up at Ham-Com last year, making a few mods to the PV power sytem in my pickup, starting the build on a new radio/etc console for the pickup and spec'ing out the parts and materials to add a PV power system to our club tower trailer. And getting ready to do a few mods to the DX-60A I picked up a couple months ago.

ldb
K5WLF

recently for thru-hole a Harris RF-590 and a video TBC, and for SMT an Icom IC-R9000 video amp module. Have not been repairing much lately but I used to do it for a living. The best thing is not having to pay others to do it.

How true, Rodger  ;D


Just heat, apparently

http://www.youtube.com/watch?v=WYo-eRLRvWQ

Good Question!

TS-830S, FT-901DM, TS-440S, FT-101ZD, FT-757, Watkins-Johnson 8716, Rayne 36 band EQ, Sony HDAM/FM Receiver (modified, not repaired), 2 or 3 FT-101E, Hammarlund HQ-170A, Ranger II, Hammarlund HQ-110, Simpson 260-3, Symetrix 15MHz Scope, Zenith (60s tube type) table radio…

 I dunno... probably some more stuff I can’t remember, but that’s pretty much lately.  I’ve been busy with my E rig and Brent’s amplifier so I’m a little slower these days.

I suppose none of this counts of course since it's not new tech, iPod, Cell Phone...  :)  Well, the Sony was pretty new tech.

Henry 2K4 amplifier -- replaced a design flawed filament choke.  Now I am awaiting the arrival of HV rectifiers to replace the FW Bridge. 

Icom R75 receiver -- resoldered the loosened power jack on the main board. 

EF Johnson Viking I  --Future project--(I need to find a "rountuit" ) electrical restoration

Admittedly simple stuff.  I hate SMT too.  I will be building a retro75 hopefully next week if it arrives soon.

John

1. Last gear repaired - my National NC-100 variant receiver.  Conductive fuzz had grown across one of the i.f. can's air variable capacitors causing a B+ to ground short.  Replaced some weak tubes and a quick i.f. re-alignment, back in service.

2.  Now overhauling (very slowly) a 1935 HRO Senior that I just inherited from my father's estate.

Fixed The ringer (plug it in the wall) of a doorbell set from Lowes.
The door buttons are radio remote so I figured it was a radio problem. Neither front nor back door 'buttons' worked.
  Turned out to be a fried (under spec'd for power demand) resistor in the 120vac drop to low DC rail.
Simple replacement with twice wattage value and now works fine.

Oh, and I put a bead of silicon caulk around top and sides, but not the bottom (moisture & bug vent ;D) of the door 'buttons.'

Just last night I fixed my nephews Peavy Classic 30 amp. 12AX7s driving 4 push-pull parallel EL84s. Biasing resistors and a broken reverb spring mount!

Those EL84s run hot don't they?   At least mine do.  It may be okay but I just don't like anything sitting there hot as hell so I put a fan on mine.

right now recapping the p.s. in my SB610.  There are two lytics in there 40 uF 350 v. that are old paper wrapped caps.  then there's the can cap and those three 1.6 and 2 x 1.2 kv tubular caps and I see a couple of what look like molded paper caps.  I'm told h.v. transformer failure is in my future if I don't recap the  p.s.

Half the problem in that, and other amps, is they hang the chassis upside-down from the top of the cabinet. All the heat rises and sits right at the sockets. It also heats up the steel chassis which ,in turn, heats up all the componants in the chassis.

I, too, have put a fan in his amp to blow the heat out. I did it 2 years ago when I replaced the once white tube sockets!

Discrete component PC boards are about as far as I go in 'modern' stuff.  Eyes not what they used to be.  Currently trying to put a BC-348Q back to close to original and get it working so that I can do a few mods to it.  Whomever had it before me made a mess of it; some of the solder joints are not even close to good.  At least I can see what I'm doing with those rigs.  And, I can find parts; at least those I don't have to make myself.

 I could Finish a White Face Johnson if I could find Channel 8 an Channel 16  :) Transmit and Receive rocks.

73

Jack.

I'm working all the time. I work for home. Mostly tube gear, I work on guitar amps for a couple of local music stores. I'll get the occasional antique radio from a couple of antique shops I do work for. I get allot of boat anchor work by word of mouth from local hams and other operators. Currently I have a Viking 2, Globe 500b, 2 Valliant’s, B&W L-1000A, and a 5100b in for repairs. So I never have time to work on my own stuff but it pays the bills.

I'll see ya in Dayton 73 N8QPC :D

An interesting tip appeared in the latest issue of Radioworld.  Rather than using a solder sucker to clear component holes in PC boards, the writer suggests using an oxygen/acetylene tip cleaner, available at a welding supply dealer.  They are under $10. The tip cleaner is made of stainless steel wire, so molten solder will not stick to it.

He suggests that you purchase the cleaner with the longer cleaning wire.  In a tight location, it can reach the solder-filled hole and works better than a solder sucker.  Perhaps it would be better to purchase several sizes since you need a size smaller than the component lead that goes through the hole. The tip cleaners have serrated edges, so the tool can serve as a miniature rasp file to clear out the remaining solder or enlarge the hole if desired.  He cautions to use care when cleaning plated-through holes to not remove the plating while cleaning the hole.

None.

Since I fixed the Gotham vertical, everything's been working perfectly here for 46 yeas now.   It's gotten so boring that I sometimes drag solid state leads across 240VAC just to give me something to do.  

Actually, new projects, maintenance and repairs never seem to end.  My own clumsiness and space-outs probably account for 20% of the crapouts.  70% comes from "big" ideas to improve the station.  And 10% is from component failures caused by pushing things too much.  

But it's better than being in a pine box with nothing to do.

T

I use a pin vise and a small drill of the appropriate size to clean stubborn holes. You can turn the drill in your fingers to clean out the holes even if they are blind.
73 N8QPC

3 Racal 6790/GM's. 2 were fairly easy, 1 had problems with all but 1 board... Why did Racal ever chose to use 16 volts tants on a 15 volt circuit?

What is BGA?

Good to see that the spirit of troubleshooting and repair is alive and well in the new technology and generation. Just saw a Best Buy ad showing recycle bins for you to drop your old electronics in when you upgrade. Talk about wasteful. You bought a new laptop? No problem - just drop the 'old' one that was working fine into this bin.

I actually went through SMT training back in the early 90s and, while not technically complex, it sure is annoying. Around that time is when I recall the 'plug-n-play, then throw-away' stuff really taking hold, like those re-badged Goldstar TV sets. A big CRT sharing a large, empty box with a tiny circuit board, cheaper to throw away and buy a new one when it broke. That's when I decided not to pursue electronics anymore as a career. If I had to deal with that tiny, plastic crap day in and day out, I'd never want to turn on another radio.

It's bad enough that the old gear keeps breaking here. Seems like as soon as I fix one, another one craps out. At least I can get my big mitts in there to work on them. Getting the time to is another matter.


Yes, the truth is once again re-affirmed as to the real secret behind the DX success at K1JJ.  ;D

BGA is something which is hard to do now that we have RoHS - Hi.

Carl - BGA stands for Ball Grid Array. When the chips gets so dense, large and programmable that you literally run out of leads, you put your device in a BGA carrier.

So instead of having a chip like A you can have the same chip look like B.

Now the fun begins - how do you solder and um - unsolder such a fine device?