Desoldering woes with a Hakko FR-301

[+DrVenkman]

Your best bet here is probably to find a schematic for the board and then try to figure out from there what component is connected to each leg that you're trying to trace: is it a resistor, a chip, a switch, etc. as depicted on the schematic. With luck your board has the component designations silkscreened legibly to help you figure it out.

[ChildOfCv]

I guess one telltale sign is if there's a copper trace leading up to a hole, but it falls just short.  That's a pretty good indication that there was once a pad there.  Especially if the area around the hole looks like bare substrate and not solder mask.

[+DrVenkman]

13 minutes ago, ChildOfCv said:

I guess one telltale sign is if there's a copper trace leading up to a hole, but it falls just short.  That's a pretty good indication that there was once a pad there.  Especially if the area around the hole looks like bare substrate and not solder mask.

That's good advice for most vintage stuff for sure. In vintage devices, the trace may be on either the top or back side of the board.

 

At some point, consumer devices started using multi-layer printed circuit boards - they may have 4, 6, maybe up to 10 layers of traces inside the board for very complex modern devices. Those make it impossible to simply follow the traces for some components. In such cases, you very much need to have a schematic to find out what is supposed to be connected to what, and help you locate test points and other components you can use to check continuity. 

[seastalker]

Thanks - I am looking for schematics now.  In the mean time, here is some dirty laundry of the board. Hopefully someone looks at them with the energy one puts into solving a crossword puzzle or riddle and might have a simple solution for some.  I have 7 capacitors left with a bad pad or iffy connection. The pics are in order for each Odds are topside, and evens are their respective bottom view. (Oops - 3 and 4 are in reverse order). On pic 3, you might see a dodgy pad next to positive that is half on.  That good side still has a good solder bond though.

[ChildOfCv]

For C1 bottom, the pad on the bottom is useful to anchor the capacitor on the board, but not electrically required.

 

Ditto for C30 bottom, C31 top, C61 top, C71 bottom

 

Did JP1 have a capacitor there?  Because it's labeled as a jumper.  As such, it should just be a wire connection.  Anyway, same as the others:  No wires need to be run, but a replacement pad would still be a good thing to prevent future pad ripping on the opposite side.

 

[ChildOfCv]

5 hours ago, DrVenkman said:

At some point, consumer devices started using multi-layer printed circuit boards - they may have 4, 6, maybe up to 10 layers of traces inside the board for very complex modern devices. Those make it impossible to simply follow the traces for some components. In such cases, you very much need to have a schematic to find out what is supposed to be connected to what, and help you locate test points and other components you can use to check continuity. 

True, but about the only way to lift an inner pad is to pull the via out.  So I'm less worried about that.

[seastalker]

THANK YOU ChildOfCv!! JP did indeed have a 47uf 16v cap there, to be replaced by a 47uf 25v.

 

Road mapping traces is where I have traditionally tapped out, so I was trying to see how you determined your findings. I think I found your formula, which may be helpful to others that someday find this page. In all cases, the lost pads are surrounded by 'a dark green island or field' and not on the light green 'copper road beneath' parts. I questioned if C30's bottom followed the rule at first, and that pads would connect to the field, but I am reaffirmed by the small circles of green that were obviously intended by design to not conduct with the surrounding copper field. 

 

You did not mention C72. I assume you meant it for the OK list with the rest? It follows the same pattern. 

 

C71 Bottom Positive - If that touches the copper beyond its dark green circle, is that a potential short? I can trim the leg a bit. My guess is no, assuming all copper roads are still beneath a layer of soldermask and only have to worry about if it were near bare metal (like the tiny dot just north of it).

 

I debate just putting the final caps in or to attempt pad repair. This is my intended personal Genesis that will sit on a shelf and play games - not to sell.  I've heard of ChipQuik  adhesive products but am still looking where to buy pads.  Do people ever DIY hack it by mounting the cap through the board, then push tiny bits of foil on the leg and using gorilla glue to hold it down (let dry before adding solder). My instincts say glue and solder merged may be a bad mix over time.

 

[+-^CrossBow^-]

The JP1 cap is required on the older models as just jumpering it would still cause issues with the game region not quite getting set right. On later variants they removed the cap completely.

 

[seastalker]

SUCCESS!! I will post a victory photo when all is back together.  I opted to put the caps in without new solder pads. If it lasts me another 30 years, I'm happy.  Even if in 15 years one of the 7 one-legged dancing capacitors dislodge, hopefully by then I'll be a pro at reworking by then.  I will skip the audio mod option since I have a MegaSG and a Mister too.  I'd probably opt for a triple bypass mod if I ever got too crazy.  As I wrap this baby up, Is there any testing that would be wise (heat or otherwise)?  Is the metal RF shield required or just suggested to prevent noise, etc.?

[ChildOfCv]

6 hours ago, seastalker said:

I debate just putting the final caps in or to attempt pad repair. This is my intended personal Genesis that will sit on a shelf and play games - not to sell.  I've heard of ChipQuik  adhesive products but am still looking where to buy pads.  Do people ever DIY hack it by mounting the cap through the board, then push tiny bits of foil on the leg and using gorilla glue to hold it down (let dry before adding solder). My instincts say glue and solder merged may be a bad mix over time.

Well, I know you can find pads, or at least you could in the past.  My mom used to do solder rework in the 70's, then wire-wrapping prototypes and one-offs for a solar observatory after that, and I inherited her supplies, which includes a huge supply of pads.

 

I at least have a theory on how to make your own though:  You can buy copper foil tape, which seems to be 3 mil thick and has an adhesive backing.  Then you can get a 1/16" hole punch.  Theoretically, you should be able to stick the chad to the pad and then pierce it with a needle.  It claims to be solderable.

[seastalker]

Once again ChildOfCv, THANK YOU!  I will look into making my own spare set of pads.  In the mean time, here are some pics as a victory run.

 

- Top and bottom of the finished VA3 revision Model 1 Sega Genesis,

- All put back together, perhaps the first recapped of it's kind in 2020, complimented by a Mega SD, brand new audio cable, an brand new M3-trio 'tower of power' all in one power supply.

- Proof via Budokan game playing!  The camera can't do justice to the HD Retrovision cables running here.

- BONUS Picture - I also managed now to recap my 32x!!!!!! 

- The 32x had pre-existing screen flicker issues, so I will look for replacement ribbons to complete this awesome all in one Sega power so I can fully Blast Process myself into the next 30 years! 

 

P.s. Does anyone know a good place to get new white ribbon cables?

 

 

Edited January 10, 2020 by seastalker

[ChildOfCv]

A starting point is here:  https://www.mouser.com/Wire-Cable/FFC-FPC-Jumper-Cables/_/N-ad930

 

But you need to know how many conductors it has (looks like 20), what the pitch is (spacing between conductors, may be in mm), total length of the cables, etc.  If you have a digital caliper, just measure the distance between the first and last pin and divide by (number of pins-1) to get the pitch.

[seastalker]

For reference to others, mine are 20-pin cables, marked "awm 2896 80c vw 1" and the width (without a caliper) via tape measure is 13/16ths of an inch, or 26/32 of an inch. I run the math later to find the pitch - too fried at the moment. I did see some cables on ebay that match the description in quotes, so maybe I will find one that matches the pitch and hope they aren't too long. 

[Cmherndon79]

On 1/9/2020 at 12:31 PM, seastalker said:

SUCCESS!! I will post a victory photo when all is back together.  I opted to put the caps in without new solder pads. If it lasts me another 30 years, I'm happy.  Even if in 15 years one of the 7 one-legged dancing capacitors dislodge, hopefully by then I'll be a pro at reworking by then.  I will skip the audio mod option since I have a MegaSG and a Mister too.  I'd probably opt for a triple bypass mod if I ever got too crazy.  As I wrap this baby up, Is there any testing that would be wise (heat or otherwise)?  Is the metal RF shield required or just suggested to prevent noise, etc.?

I think it is okay to run without the RF shield, but they certainly do use that for extra heat dissipation.  I always put them back on, and I like to put a bit of thermal compound between the voltage regulator heatsink and the RF shielding, both upper and lower pieces.  Better heat dissipation is a good thing generally.  After I recap one of these I like to have it run Gunstar Heroes for 24 hours, just in it's attract mode.  It's a pretty late title that pushes the system pretty well. 

[Cmherndon79]

Oh.  And congrats! Getting a model 1 Genesis recapped and working is tricky and if you've done it, it's an accomplishment!  The VA3 and later revisions are especially tough.  Sounds like you've made a lot of progress in the past month.

[seastalker]

Hey thanks Cmherndon79!  I do feel very proud of having the Genesis done how I'd like it. I did put Arctic Silver 5 on the black surfaces of the voltage regulators and ensured they hugged the metal plate well. I did forget to put the plate on when I used the bare board to test just for the photo but I had it on for maybe 3 minutes.  I did see on reassembly that the shield in this scenario would be wise to keep as a large heatsink. I did the 32x the same day, and the next day I powered through my PC Engine and Panasonic 3DO with surprising ease.  All of you helped me to look at the big picture and it just clicked. I plan to get more cap kits.

 

If I could, I'd rename this thread title more positively: "Desoldering WHOA!s with a Hakko FR-301"

 

If I may offer, I found the re-capping method that works best for little old me is this:

 

1. lay out and organize all your caps from most quantity to least (a strip of 8 or so vs the 4's and 3's, then the specialty caps you only have 1 or 2 of)

2. Confirm your caps match your motherboard revision, and do a brief overview of cap locations and if they match your reference sheet to CHECK OFF as you go.

3. It is now safe to remove old caps WHEN CLEARLY MARKED FOR POLARITY to save from looking it up later. Boards may differ as to which method is best:

 

a. Method 1 (preferred)- take a flux pen and dab all points you wish to desolder, usually on the bottom of the board. Put your finger on top of the cap,

and as you use your desoldering gun on the reverse side in a circular motion, wiggle your finger slightly on the cap as if TESTING if your tooth was loose. This will let you know if the leg on the desolder side is free, and if the leg wiggles, it will help keep it from re-adhering to the solder pad as it cools. This also may help minimize your heat on the board and hopefully help you not lift a trace or solder pad. Repeat for the other leg and remove the pin. NOTE: if the solder isn't coming out, good thing you added a dab of flux! Just add a dab of new solder to the old and try again.  Remove the cap when both legs are loose. 

b. Method 2 (more time consuming)- cut the capacitors off, leaving the legs and solder for desoldering afterward, using mostly the method above.

 

4. Clean all solder pads with isoprop.

5. Using your cheat sheet of uf and voltages, insert all the new caps in one at a time WITHOUT trimming any legs: each being mindful of negative polarity markings both with the stripe on the cap and (hopefully) on the motherboard silkscreen indicators.  With each cap placed in, on the reverse side, bend the legs in opposite directions to loosely keep the cap in place no more than a wiggle. Leaving the legs is a grand reminder for your checklist, confirming they are indeed new ones. Repeat with all caps but DO NOT SOLDER YET!

6. Confirm all caps are where they need to be and in the correct polarity, AND ensure no cap legs are in the path of something where solder might fuse to it accidentally, then hit your solder pad/legs with another dab of flux and use your soldering iron and solder on each point. 

7. Confirm all joints look good on BOTH sides of the board. If top side solder joints looks good, thank the bottom side solder fairy. If a needed topside solder joint needs more, resist soldering there so you don't burn the bottom of the capacitor. Instead, find its leg underneath and add a dab of flux and allow your solderer to rest on the solder just long enough where the density of it "feels" like it seeped below to topside, and check topside to confirm.

8. Clean each solder point with a cotton swab of isoprop and now is good to clean any old residue, being CAREFUL not to dislodge any surface mounted components, then trim the capacitor legs using a fingernail clipper if not a specialty tool. Lift each leg out of the way and trim as close as you can without taking a chunk out of your round solder on the joint. You may want to do a final isoprop cleaning (or suggested electronics cleaner) to ensure you don't have bits of solder or a capacitor leg still laying on the board in waiting to short it out.  DONE!!

 

[+-^CrossBow^-]

Only thing I do different is that I actually change out the caps one by one instead of removing them all at once. Reason for this goes back to when I started which was originally doing cap jobs on arcade monitor chassis boards. Often the values of the caps would get changed out as some games or monitors might require a different value in certain places be used. Because of this, I often found cap kits that would use a standard value cap that is on most spec sheets for the chassis, but then in reality you find out a different value was needed for this tube that was in use. As a result, I would be stuck with having to get the proper value cap for the job since it wouldn't be in the kit. If I had removed all the caps all at once and then inserted them all back in, I would have started to second guess when I followed the sheet and found my video image off the side or distorted because a cap I removed was different than normal. And as a result of removing all of them, I'd would now not know which cap it was that was actually different. 

 

I'm stating this because I've had it happen to me. From then on I now do all recaps one at a time. I find the cap, use a silver sharpie to mark the negative lead on the bottom of the PCB. Add a bit of solder to both leads and then use my fr-300 doing exactly what you stated where I keep one finger on the top of the cap and wiggle as I use the desoldering gun. I then put in the replacement cap matching up the polarity and solder it down and clip the legs. I then mark off on the map sheet which cap i just did so I know where I left off when I come back at a later time to finish if I don't do it all right then.

 

I still occasionally run into differences in the kits vs what is in place but mainly when I'm doing a recap on a revision that isn't well known. Also in the case of the Genesis model 1 units. I start along the back right side near the CD expansion port and work my way around the board in a counter clock motion. I actually do that with most boards as it also helps to keep me in a pattern of where I've been vs haven't been.

 

 

[seastalker]

On 1/9/2020 at 10:27 PM, ChildOfCv said:

A starting point is here:  https://www.mouser.com/Wire-Cable/FFC-FPC-Jumper-Cables/_/N-ad930

 

But you need to know how many conductors it has (looks like 20), what the pitch is (spacing between conductors, may be in mm), total length of the cables, etc.  If you have a digital caliper, just measure the distance between the first and last pin and divide by (number of pins-1) to get the pitch.

Sadly, I did not find a result there. Ebay options are some guesswork unless you buy another broken 32x that may have the same problem. I wonder if I might make an odd "cable" by soldering wires directly from point to point, or to the ribbon cables' exterior with enough of each pin to be seated. I have to look at the connections again. The former option might be better  so nothing gets unseated.

[ChildOfCv]

If you're just looking for a replacement, a longer cable than what was originally in use may be satisfactory too.  It just needs the same number of pins and pin pitch.

[seastalker]

I had a chance to test each and every pin on both 20 pin white ribbon cables for continuity and all is fine (I also tested the ribbon cable in my Saturn successfully). Is that conformation that the cables are not the problem or does a scenario exist where you could get pin continuity on a damaged pin depending on if the cable is flat vs in its factory establish c-shaped state of rest in the console? I'm checking the connection points on the 32x too.

[ChildOfCv]

The only way to be sure would be to connect the cable, then probe all the connections from one board to the other (past the plug on both sides).

[seastalker]

I want to notate this troubleshooting for others, knowing that the Sega 32x can be a tricky thing to get working. 

 

I got a working 32x (revision VA 1 board) to go with my one with issues (VA 0). Here is the timeline:

 

1. Sega 32x VA0 doesn't work.  Cleaned it and it worked.

2. Came back to it weeks later and I get audio and picture, but picture is flicker-city and distorted.

3. Ordered recap kit form Console 5 and recapped it all, but problem persists.

4. Muti-meter test on all pins of two white ribbon cables showed no problems.

5. Researched revisions and found that the top board is the same on all but the bottom cart slot has VA0, then more reliable VA1 and bought a working 32x of the latter.

6. Saw Kevtris's 32x guide and on the recapped VA0, I re-recapped the one barrel cap and the one surface mount cap on bottom board- no difference. I borrowed the white ribbon cables of the new one- no change. 

7. To pinpoint the problem, I took pictures (see below) of all wires connecting top and bottom boards and swapped bottom boards (again, top boards are all the same) between my two 32x units.  Lucky 7!  They both worked perfectly! I had two working 32x's for some unknown reason.

 

**Notice in the pictures, that Sega opted for different points for the ORANGE wire between revisions. 

 

8. Wanting the new surface mount cap on the bottom board, I swapped those between the two 32x models... and the screen flicker came back on my original 32x problem even with the new lower board. UGH!! I thought the problem must be this surface mount cap but swapping back, and the problem was still there. So if not the cap, I re-tinned the video output jacks and the solder points of both ends of each connecting wire between top and bottom boards. When all was said and done, I knew that BOTH lower boards were fine because the newer 32x accepts both the VA 0 and VA 1.  The lower boards hold all the specialty chips so that is the good news.

9. I re-checked polarity on all my new cap replacements even though the issue pre-dates that task. Thinking it must be the wires, I reconnected each. 

10.  Stable picture now, but the screen was heavy on the RED hues.  These wires must be the culprit.

***11. Messing with each wire individually, the BLUE wire connected to pin 8 on the white ribbon header lifted... with the pad/pin underneath!  ARRGGHH! [More on this down below]. Without this wire connection, I got no picture or anything. I jammed the wire in and the solder pen adhered it to SOMETHING inside. 

12. I powered on the 32x, and it now ALMOST works!  I have correct colors, and Star Wars 32x looked fine until the destroyer ship in the opening fired weapons and the screen is now doing minor flickers, but not more flickering like you threw the V-hold or sync out of whack. I laughed because the AUDIO makes the flicker now- it's like the ship's weaponry in the Star Wars intro is too "awesome" for the 32x to handle so it must flinch. That's my one handy OG 32 x game so I tried the Mega SD and some Genesis carts. All work fine until I load a 32x game where the "sound causes flicker" issue is there. Tested with Afterburner 32x.  Being fair, if it IS the blue wire's fault, PLEASE PLEASE someone help me trace that pin 8 to an alternate location so I might try again with a sturdier solder point. I wonder now if my original issue was a liftING pad on pin 8 before it finally went.

 

I really want to share my findings with a fully recapped in 2020 Sega 32x with Kevtris fix compared to a non-recapped one. I'll then recap the other one and compare re-cap to re-cap, but with only one having the Kevtris 2x cap mod.

 

So if anyone can help me pinpoint this problem for others, here is the help I need. I need to find where blue wire pin 8 can have an alternate solder connection for the blue wire. I looked at the service manuals and schematics here: https://gamesx.com/wiki/doku.php?id=schematics:console_related_schematics  ...and realized that schematics are greek to me. I looked with a magnifying glass. Pin 8 was by design or afterthought NOT fully connected like the other pins on the ribbon header, nor can I see where this pin leads to on the VA1. It almost looks like a metal stub of the pin is above.   On the VA0, there is a Sega technician's cut trace as per what they did in Sega's in house repair guide. 

 

Now, 10 pics of a VA 0 vs VA1 . Again, note the orange wire placement differences while the others are the same. Note the pic descriptions 2.  Any help on that blue wire especially would be so greatly appreciated.  These 5 or so connection wires may be important 32x troubleshooting so hopefully Kevtris or Smokemonster's recent experiences lend themselves to comment on this.

 

Thank you all.

Edited February 13, 2020 by seastalker

[seastalker]

I found a reddit post that may be very handy for those needing replacement white ribbon cables:  get 4x of these:

https://www.digikey.com/products/en?keywords=HF20U-02-ND

 

Original reddit post:

 

Aaron707

 

Ive replaced the ribbon cables with shorter ones when I built a neptune for my brother.Here is the part: HF20U-02-ND

https://www.digikey.com/products/en?keywords=HF20U-02-ND

You will need four of the above part and place two back to back to make one ribbon cable. Nice tight fit with no issues. It allowed me to get everything very compact. I also used wire to relocate some of the genesis capacitors near the cart slot so the upper 32x board could be lower when sandwiched. Also a good idea to recap the genesis and 32x before doing the mod. I had some faulty caps on my 32x and wished I had replaced them before modding as its much easier.

 

I wonder if the model 2 Neptune hack also can fit a triple bypass mod. If I can get this 32x working I will have an extra one so maybe a Neptune project will happen. My next fix may be a replacement 64 pin cartridge port from a dead donor model 2 genesis to replace the 32x one. If that doesn't work, I guess I'll try a new voltage regulator(s) where needed. 

 

[seastalker]

I've now desoldered the 32x cart connector and replaced it with one from a spare Genesis 2 to see if the cartridge slot was the issue. I at least like the tighter fit for both genesis games and 32x, so if nothing else, it was worth it, though it did not fix the problem. In the pix you can see a clean top and bottom of where the pin connector was, then a pic where the deeper pins (site rotated the pic) on the left are theGenesis 2 and the more copper showing on the right is the old 32x one.  You can then see a Genesis Hockey game NHL 96 where the video still glitches, and then Star Wars 32x doing the same behavior as when I started.

 

Remaining remedies: Could the top board's copper coil have a defect that would cause this (if so where do I get a replacement when I don't even know what it is?)?  I have heard that if a previous owner used the wrong power supply then the voltage regulator could need replacing.   I also have the new problem of blue wire seen above on pin 8 of the lower pcb's ribbon connector.  I hope someone sees my last plea for knowing an alternate place I can solder that wire to on that end. Otherwise, I may be looking for help finding a 32x pro repair I can send it to.   I feel so close yet so far. 

 

[seastalker]

Would anyone be able to kindly offer advice on how I can look at the schematics of a 32x and learn how to follow them? I specifically hope to trace that problem of the blue wire seen above on pin 8 of the lower pcb's ribbon connector.  I've stared at schematics and have yet to figure out how what I am looking at translates to a pcb.  I look at the one, then the other and have yet to find a "you are here" sign I can make heads or tails from.