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Post by Boomzilla on Apr 18, 2020 16:36:36 GMT -5
I need to remove the printed-circuit board from my Dahlquist DQ-LP1 crossover so I can work on the thing. Having removed the top and bottom of the case, the stand-off screws, and having removed the knobs from the faceplate, the only remaining impediment to removing the board is the AC anchor. The power cord is a two-conductor "lamp cord" looking thing and where it enters the back of the chassis, there is a push-in, plastic UL strain relief. This anchors the power cord to the back of the chassis so that the power cord can't be yanked off the printed circuit board if the power cord is stressed.
The outside of the strain relief appears to be a solid ring of plastic. But the part of the strain relief inside the chassis is much smaller diameter (as it would have needed to be for insertion). A plastic tab sticks off to one side of the strain relief.
How do I remove the strain relief to pull the thing out of the back of the chassis?
I see several potential options -
1. Use some needle-nosed pliers to pinch the tab back into the "body" of the strain relief while pulling on the strain relief ring from outside of the chassis. If I can get the inside diameter of the strain relief back to its original size, the thing should just slip out.
2. Cut off the strain relief and throw it away. But this risks also cutting the power cord insulation.
3. Yank the tab off of the inside of the strain relief?
So despite my Google searches and YouTube browsing, I've found no information that is pertinent to this question. Do any of you know the "trick?"
Thanks - Boomzilla
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klinemj
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Post by klinemj on Apr 18, 2020 16:49:34 GMT -5
Try a blow torch. That will remove the impediment. It might damage other things, but the anchor will be gone. Mark  |
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DYohn
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Post by DYohn on Apr 18, 2020 17:06:20 GMT -5
If you are talking about the plastic device the power cord passes through on teh back chassis, unsolder the power cord from the PCb and the fuse holder then use pliers to squeeze the plastic against the cord and then pull it out from the back.
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Post by Boomzilla on Apr 18, 2020 18:54:09 GMT -5
Did it. Thanks!
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klinemj
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Post by klinemj on Apr 18, 2020 19:43:09 GMT -5
If you are talking about the plastic device the power cord passes through on teh back chassis, unsolder the power cord from the PCb and the fuse holder then use pliers to squeeze the plastic against the cord and then pull it out from the back. Shoot - I wanted a video of the blow torch approach. There you go spoiling all my fun. Mark (PS - the isolation may be getting to me. but...the blow torch...) |
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Post by Boomzilla on Apr 18, 2020 20:01:10 GMT -5
Tomorrow, I'll unearth my solder-sucker and remove the existing op amps. 10 new NE5532p chips with sockets are on order. If I got the wrong ones, then I'll have to upgrade the box to an external power supply. I've also ordered new 0.12 uf Sprague Orange Drop caps for the high-pass section. I've tried polypropylene and Teflon dielectrics, but they sound too smooth to my ears. The Sprague caps are a good balance between the harshness of ceramic, non-polarized electrolytic, and tantalum caps and the rounded-off sound of the fancy ones. Plus they're cheap!
Since the input impedance of the Emotiva PA-1 amps is 22,000 ohms, the 0.12 microfarad passive caps should yield a crossover frequency of 60 Hz. For my Airmotiv S-15 subs, this is about right. If I had Emotiva's smaller subs, I could probably cross over at higher frequencies (based on Emotiva's anechoic curves).
Cheers - Boom
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Post by Boomzilla on Apr 20, 2020 4:25:59 GMT -5
My solder sucker no longer sucks like it used to. I suspect that enough solder has accumulated inside the vacuum tube that it's got the equivalent of arteriosclerosis. To clean it, I'll need to remove the vacuum bulb and fire up a small propane torch. Then I can heat the tube and melt all the accumulated solder. This IS an outside job...  In the meantime, I've ordered a roll of solder-braid, and will use that to absorb the remainder of the solder that I need to remove. But I've also discovered that the NE5532p chips that I've ordered, despite being pin-compatible with the original chips, also draw about twice the current. The onboard power supply can't supply that much and the voltage drop will be insufficient to power the five chips on the board. So my options are two - find some pin-compatible chips that draw no more current than the originals, or replace the internal power supply with an external one of greater wattage. The DIY Audio forums are being a GREAT help as I move forward with this project. |
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klinemj
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Post by klinemj on Apr 20, 2020 9:02:07 GMT -5
My solder sucker no longer sucks like it used to. I suspect that enough solder has accumulated inside the vacuum tube that it's got the equivalent of arteriosclerosis. To clean it, I'll need to remove the vacuum bulb and fire up a small propane torch. Then I can heat the tube and melt all the accumulated solder. This IS an outside job... In the meantime, I've ordered a roll of solder-braid, and will use that to absorb the remainder of the solder that I need to remove. But I've also discovered that the NE5532p chips that I've ordered, despite being pin-compatible with the original chips, also draw about twice the current. The onboard power supply can't supply that much and the voltage drop will be insufficient to power the five chips on the board. So my options are two - find some pin-compatible chips that draw no more current than the originals, or replace the internal power supply with an external one of greater wattage. The DIY Audio forums are being a GREAT help as I move forward with this project. It sucks that your solder sucker no long sucks solder like a solder sucker should. Good luck in your quest to get your sucky solder sucker sucking successfully soon! Mark |
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Post by Boomzilla on Apr 20, 2020 9:19:12 GMT -5
It sucks that your solder sucker no long sucks solder like a solder sucker should. Good luck in your quest to get your sucky solder sucker sucking successfully soon! Mark Evidence of excess caffeine? But it IS funny - I nearly spit my coffee when I read this. You're getting better in your old age! Thanks for the levity - made MY day much better.  |
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Post by SteveH on Apr 20, 2020 15:24:59 GMT -5
My solder sucker no longer sucks like it used to. My ex-wife is in the same category as your solder sucker!!!!! |
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Post by 405x5 on Apr 20, 2020 15:39:14 GMT -5
Yeah I know (been too long in the house!)  |
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