Anyone familiar with Collins HF8050 rcvr?

[wb1ead]

Hi guys..I had a topic ready to post and thought better of it..this will sound like an odd comment but I really don't want to be specific if no one here has knowledge of this rcvr..no need to tie up a forum and waste space..however having said that I will at least give the basic wants/facts..I've come into a Rockwell/Collins HF8050 rcvr for zero $$..it is DOA..two crispy critters on two seperate boards..charcoalled so bad as unidentifiable..a resistor and a cap..I have found NADA info no matter where I turn..there is no manual and I'm not about to spend mega-bucks for what one individual seeks..$200+..this is not the kind of rig you stumble across over and over at a fest..yes I WILL BE MORE specific if someone actually can help..BAMA/MODS DK/ and the like are no help..unless I missed sumptin..I need the values of these two critters..I hate guessing.........I did not intend this posting to be a slam to anyone on their basic skills on troubleshooting..this really is a honest to gosh specific request for a real rare not often seen rig.......if I did this request the wrong way I apologise..this is frustrating me and I have no other places to turn.........many tnx!
                                                                  73 de DAVE

[w3jn]

Sheesh, what's with all the apologizing?  That's what the forum is here for.  Bandwidth is dirt cheap. 

Everybody learns by threads like these.  Not saying we'll ultimately be able to help, but post it and we'll see!

[wb1ead]

OK John you talked me into it..for those who may not know John has always taken the time to read my e-mails to him..so we are acquainted and he IS a rcvr guru!..for sure!....OK here goes..this rig has numerous plug-in type PC boards..larger main boards and several smaller side boards..it is there with the side boards that the crispy critters reside..output board assy 635-4930-002 Rev M..sub assy 635-4925-002 Rev G a 1/4 watt resistor possibly tied to transistor 2n5109..on voltage regulator board assy 635-0656-001 Rev C a small black cap very near 8 pin IC F8151....both of these are burned to a crisp and no color bands/markings can be seen..these are the only two I could find after a thorough scan of each board unplugged thru a lighted magnifier..the rig DOES power up and the meter lites but no audio and the rcvr fault lite is on......I DID find a source of spare boards(overseas) but I'm not the winner of the Powerball lottery..thanks!              73 de DAVE

[w3jn]

Well guess what.  Our old friend the 851S-1 is pretty similar to the HF-8050.  The 851S-1 has a knob to crank and a LED display, but other than that I don't see too many differences.

THe best thing is mods.dk has the manual for the 851S-1.  You have to register to download stuff, but hey, it's free.

There's a skizmatic for the synth regulator board; the synth output board has a slightly different number but hopefully it'll get you close.

Download the zip file, unzip it to its own directory, and click on the "index.html" file in its root directory.  Someone did a REALLY nice job of organizing the manual, it's broken into sections etc.

Link to the mods.dk collins page is here http://www.mods.dk/manual.php?brand=collins

[w3jn]

Looks like the fried cap on the synth regulator board is either C1 (10 uF tantalum) or C4 (15 uF tantalum).

Not enough info on the fried resistor, you'll need to look at the data to figure it out.

As an aside tanatlum caps of this era are notorious for shorting.  First suspect in professional receivers like this.

[WA1GFZ]

I think Big Al K1JCL may have the book.

[Fred k2dx]

You could ask on the Premium Receiver group...http://kahuna.sdsu.edu/~premium/

update: Well, maybe not. I haven't been on the list for a while and it seems to have become inactive or changed name... I will post if I can find out what happened to the group. Some manuals were posted in resources there.

[wb1ead]

Wow you guys are awesome!..John I think it's the 10uf..as the 15uf is sitting just to the left of that..on the resistor I'm still not certain..I'm gonna have to keep scanning the output board schematic..I think I've got it but one more peek again..all 3 of you..John Frank and Fred thank you and sorry I couldn't respond faster as momma had the putor for awhile..I will promise to keep you informed as to the progress either way.....I was aware that the rig had other clones if you will actually upgrades of the basic design..if I'm not incorrect I think they start out with the HF8050 then HF8050A and lastly 851S-1..ur right John the sub-assy is somewhat similar except for placement of the components it looks like..almost vice versa..thank you all and God bless!
                                                          73 de DAVE

[Fred k2dx]

The Premium Receiver List is now here: http://mailman.qth.net/mailman/listinfo/premium-rx



Good luck with it.

[wb1ead]

As promised here is the sad update on the rig..I did seriously study the schematics and replaced the two components in question..flipped the switch..no snap/crackle/pop but not much else either..the only differences are no hum and the S mtr does barely wiggle when changing modes and such..but she remains DOA..for someone not familiar with this I'll assure you it's WAY outta most folks leagues..snap in/out circuit boards that require extenders to service is not my cup-o-tea..it's headed for E-Bay and such as that as a purely parts only rig..damn shame too as it has over a dozen boards inside..built like a tank and Collins sold them for Mega-Bucks $$..betcha it sounded sweet once upon a time..I for one hate to throw in the towel but reality is here..Thanks to all who tried to help..I got some off board E-Mails on this and again to all THANKS......73 de DAVE

[WA1GFZ]

usually the deader they are, the easier they are to repair

[w3jn]

Check voltages.  The boards have test points as described in the manual. 

You don't have the card extenders so you have to solder a pigtail wire to the test points. 

The fault light, as I recall from looking at the schematic, will illuminate if the synth is unlocked or any of the voltages at the PS are out.  So if the fault light is off the synth is probably doing its thing.  It's easy from there... it's just like any other radio.

Probably just as well to eBay it though.  Although it's a FB radio (I had a 851S-1 some years ago) the thumbwheel tuning is a pain in the ass for band cruising.

[wb1ead]

Thanks John for the tips..got a call from a tech type somewhat familiar with Collins..says I should recheck the 5 main boards and be doublesure they're locked into the card slots..yud think that such a hi-quality pc of gear would have a generic reset of some kind..puzzling as the components replaced did not go pop after power on..twice as puzzling was the total lack of support from the CCA gang..yud think someone there woulda been down this road once..in a nutshell...too complex/too sophisticated/and pretty damn rare..and yes that thumbwheel tuning looks to be one big pain in the keester for surfin the bands..everything in life is a learning experience John..in a few days class will be over for my hi tech hunk-o-gear.....unless Mr Luck comes calling!
                       Thanks agn John..have fun in SV land..send dry weather to New England!!!        73 de DAVE

PS: I DID check the voltages on the power supply..OK..will have to look at the individual boards focusing on the RF module (A9)

[WA1GFZ]

start from the speaker and work your way in.
Much easier than starting from the antenna end

[wb1ead]

Tnx Fred..I will do my best to doubleck all..I'm really reluctant to open the A9 RF module as it's a sealed unit..so basic re-checking will be in order..the only positives are it stopped humming in the spkr and the S mtr jumps very slightly when clicking thru the meter switch..I will also try the headphones jack which for some reason I haven't tried since replacing the two components
                                                                 73 de DAVE

[w3jn]

Is the FAULT light off?  If it's still on, the synth is probably unlocked.

There is probably a mute if the synth is unlocked.  I'd force the mute open, then inject a 455 KHz signal into the 455 IF input and verify that's all working.

If it's a synth problem it could be as simple as the reference not working, or one of the VCOs has drifted so far off it can't be corrected by the loop.  You can verify with a scope or a receiver.   The signals from the VCOs should be stable.  If they're drifting at all you can bet the loop isn't locked.

[WA1GFZ]

When a loop is unlocked I go right for the phase detector then work my way through the loop to see if the output voltage agrees with the duty cycle of the phase detector. Todd's KWM380 had a leaky silver mica that yanked the loop in the opposite direction of the phase detector. Yes many receivers mute when the loop isn't locked Todd's made a beep. If your S meter is at zero and there is no audio noise with a unlock led lit you can bet the CPU shut the radio audio off.

[AB3L]

..twice as puzzling was the total lack of support from the CCA gang..yud think someone there woulda been down this road once..

Did you try the archive section of the CCA website? They might have gone over some problems in the past.

Maybe a phone call to Wayne Spring might help to guide you. He has been the master of the 380 and maybe has some experience with the 8050. You mentioned the $200. service price tag, maybe you were referring to him already and that was his quote? If not his info is on the CCA site under the Directory section.

Also, did you try the Collins group on qrz.com?

Bob

[WA1GFZ]

The 380 is an easy rig to work on because you don't need extenders.

[wb1ead]

Hi All..I haven't been sleeping on this..but no progress to report at all..tnx Bob for ur tips..the $200 tag was for at the time a manual for this rcvr on E-Bay..Wayne appears to be "the Guru" for all things 380..and yessiree I did research the CCA site archives for any sort of tip/help there..even left an inquiry asking for help..I was not aware that QRZ had a Collins group active..I looked..didn't see anything.......Fred is right..the KWM380 is from what I've heard too a much more user/repair friendly rig..at this time it does hiss ever so litely thru spkr cranked AF all the way..the rcvr fault lite is still on..goes out on removal of A10 board?..I doubleck'd again all boards for loose connections and apparent bad guys..nothing looks outta place....there is one troubling thing that I'm not about to experiment with..the main big boards A6 thru A10 can only locate in the edge connector spots for that particular board..and yup they are marked on the chassis edge..no mis-placement there..however the 8 side boards actually could be mis-placed..no marking on chassis and a few of the boards COULD be made to go where they're not supposed to go?..I cannot figure the proper sequence of "who's on 1st?" etc etc..this is the order now as viewed from front to back..1st Volt Reg..Ref Std..(skips a spot?)..End Decade..100/10HZ..1KHZ..10KHZ..100KHZ..Output....it is I guess possible that they are not in the right order..that is the last thing I want or hope to sort out..this rig would be a PERFECT test/fix for an aspiring class on Electronic Troubleshooting..Thanks to each and everyone of ya for ur input and tips..if a miracle occurs you'll hear my yell from up here in Moose country!                    73 de DAVE

[WA1GFZ]

don't swap boards around unless you want to really trash it.
Making crazy guesses just makes things worse. Someone worked on Todd's 380 before me. I could see the trail of replaced parts because the repair person was clueless. The problem in his synthesizer was just a leaky cap in one loop filter.