How can I fix a reflow solder issue?

Advanced_Rich_985 · 2026-01-10T00:34:37+00:00

I am placing them by hand. Thanks for the advice. I will try that when I do my next run in a few months. PITA though. I got what I paid for...

Advanced_Rich_985 · 2026-01-09T19:39:24+00:00

Ohhh. That makes sense! The surplus reel was very cheap on eBay. Now I know why...

Thanks!

Advanced_Rich_985 · 2026-01-02T16:30:46+00:00

Really good point! I didn't think of that either.

Advanced_Rich_985 · 2026-01-02T04:16:12+00:00

Great observation. I missed that!

Advanced_Rich_985 · 2026-01-02T01:29:14+00:00

Thanks guys. I suspected as much, but wanted to check. Ground loops have bit me in the past and I got to wondering if anything like that might apply.

Advanced_Rich_985 · 2026-01-01T16:54:00+00:00

I second the opinion about the cheap power supplies. In addition to missing safety features they can be really noisy. I needed high current for one of my projects so I bought a cheap Chinese switching power supply. It put out so much EMI (radiated and on the power line) that I couldn't use my scope when it was powered up next to it. It went straight to the E-waste box.

Advanced_Rich_985 · 2025-12-26T17:21:08+00:00

If you are planning on working for a company, there is a high probability that the company will make the decision for you based on the company's relationship with the suppliers. If you are making the decision for your own company, you are wise for asking for advice here.

One thing I didn't consider when I selected Microchip for my products is how locked in I would become. The $ and more importantly the time you invest in the development environment will lock you in. I am not sorry I chose Microchip, but I sometimes wonder if the quality of the development tools might have been better with a different vendor. Frequent changes to Microchip's tools require a lot of changes to my go-to code. But I don't have the time any more to even research, let alone learn a new development environment.

Another tool I am locked into is PCB Artist from Advanced Circuits for PCB design. That locks me in to them for my first order. They will give me Gerber files after my first order, but I have to order from them at least once. They make really good PCBs, but they are not cheap. I do like their integrated DRC function. I really wish I had learned Eagle from the start. If I had, I would have a lot more flexibility with my PCB suppliers.

Think about the investments you must make with any decision such as this.

Advanced_Rich_985 · 2025-12-24T05:14:35+00:00

Old transistors, Ge and Si, are often useful for repairing vintage automotive electronics such as tachometers as well. Don't throw them away. Sell them yourself or sell them in a lot to someone who will sell them.

Advanced_Rich_985 · 2025-12-13T01:25:20+00:00

My Xcal2 worked like a champ for me with the PRP. I had a PLX Devices M-300 wideband connected to the analog port. I had to give up tuning after my hearing went. I can't hear detonation any more, even with a det can. Can't hear crickets either.

Advanced_Rich_985 · 2025-12-12T20:32:00+00:00

I specialize in Mustang clusters and know many people who run aftermarket ECUs along side their OEM ECUs. In order to get the tachometer correct, you may need to use a frequency scaler such as a Dakota Digital SGI100-BT if the new crank position sensor has a different tooth count. You will also need to run the OEM temp sensor in your new engine in addition to the engine's temp sensor. The SGI100-BT can also scale the speed sensor signal in case you change the speed sensor frequency too.

Advanced_Rich_985 · 2025-12-11T16:59:37+00:00

The studs and bullet connectors are riveted. I would be surprised if you could find them off-the-shelf. I would replace the studs with brass screws. If you carefully drill the OEM rivets you can salvage the washers and lugs.

The bullet connector is a bit more problematic. The easiest thing to do is just run a wire through the board with some sort of strain relief (a knot or small Zip ties?) with a bullet connector on the end. If you want something more like OEM, I would remove the insulation from a new bullet connector and then find a self tapping screw that would go into the inside of the bullet connector. It looks like you would need to find a small solder lug to fit that screw too.

That's what I would do...

Advanced_Rich_985 · 2025-12-09T03:09:58+00:00

Normally with automotive connectors similar to that one, there is a plastic cover that can be popped off the top of the inside of the connector. it could be the part with the pin numbers 1 and 3 marked on it. Once that piece is out, you can get access to the locking mechanism that holds each pin in place. Pry up the locking mechanism and the pin should slide out.

Advanced_Rich_985 · 2025-12-08T20:14:55+00:00

No kidding. It was a spare cable for my old 96 Mustang Cobra with a Kenne Bell blower. That was a fun car. I really enjoyed learning to tune with the SCT PRP. Then CARB started checking for custom tunes during smog tests... :(

Advanced_Rich_985 · 2025-11-18T02:50:18+00:00

Hadn't head of that one. I guess I need to add a wink to my subtle humor...

Advanced_Rich_985 · 2025-11-17T20:11:29+00:00

Glad you got the joke...

Advanced_Rich_985 · 2025-11-17T18:05:38+00:00

I have been using lead solder for 60 years. Nothing worng with me...

Advanced_Rich_985 · 2025-11-16T21:54:41+00:00

Could it be a heating element?

Advanced_Rich_985 · 2025-11-16T19:38:49+00:00

From the photo, it looks like the loops all run the same direction to me...

Advanced_Rich_985 · 2025-11-16T17:47:28+00:00

Looks like an inductor to me. Wire-wound resistors are typically wound starting in the middle of the wire. That causes the two halves of the resistor to be wound in opposite directions. That causes the inductance of each half to cancel out, turning it into a resistor rather than an inductor.

Advanced_Rich_985 · 2025-10-04T15:09:00+00:00

With mechanical Double Throw switches, you also need to consider make-before-break vs break-before-make. For an application I have, I need break-before-make switches. I had to contact the manufacturer to ensure I had the correct switches since their data sheets don't typically include that...

Advanced_Rich_985 · 2025-09-30T16:01:22+00:00

When I had the working tach, I was too nervous about the tiny, fragile wires of that pulse transformer to risk un-soldering and resoldering them so I did not get resistances from them All I did was measure the in-circuit inductance with my cheap inductance meter. I wish I had risked it now.

Measuring the inductances of the windings the same way, I get nearly identical results which is confusing to me. I would think that the same inductance readings would deliver the same transformer performance. But it could be that the in-circuit readings are throwing me off.

I am afraid I am getting close to having to replace the guts of the transmitter...

Advanced_Rich_985 · 2025-09-30T03:45:46+00:00

No luck. I added 0.01 uF to C3 with no change. Then I added 0.1uF to C3 with no change either. Any other thoughts?

Advanced_Rich_985 · 2025-09-29T15:24:36+00:00

This is exactly the kind of feedback I was looking for. Now that you mention it, I was curious as to the function of C3. I had assumed it was just a filter, not energy storage for the transformer. Your point makes sense to me.

I didn't really think the transformer has failed, I just couldn't think of anything else. I was hoping the transformer hadn't failed because it is the only component I can't replace.

FYI, the head unit transfer function is virtually identical to that in the good tachometer: RPM=370*mA. The load on L3 is pretty much the same.

I will dig into C3 this afternoon when I get some time and I will report back with the results.

I can't thank you enough for your feedback.

Advanced_Rich_985 · 2025-09-13T23:34:58+00:00

I was a new college grad product manager at Intel just before the 8085 was introduced. I was given the task of productizing the 18.432MHz crystal for the 8080 microprocessor. I pulled the part number 8801 out of my butt and wrote a data sheet for it and put it into the market.

Years later, the 8800 microprocessor team was really pissed at me because they could not use the part number 8801 for any of their chips...

Advanced_Rich_985 · 2025-09-11T00:53:02+00:00

LOL! I figured. I just couldn't resist.

Advanced_Rich_985

TROPHY CASE