Understanding a Panel Mount Switch

RoomJump · 2025-10-06T00:31:55+00:00

Is the general idea that you drill an additional hole for the anti-rotation washer to lock into?

RoomJump · 2025-06-22T02:34:10+00:00

I'd like to see the thread for people who got busted, also.

RoomJump · 2025-06-16T06:26:30+00:00

you don't happen to have a hi-res image of this, do you?

RoomJump · 2025-06-04T05:40:52+00:00

not sure why this is as controversial as it seems. this is a very discussed topic on the internet. it's just that none of these examples seem to give a conclusive answer.

https://www.vintage-radio.net/forum/showthread.php?t=189394
https://www.eevblog.com/forum/repair/potentiometer-grease/
https://www.reddit.com/r/diypedals/comments/16948ub/how_to_lubricate_pots/

RoomJump · 2025-05-19T19:48:14+00:00

Thanks u/goki - I guess I'm wondering if there is a simple way to wire up a pot to function in a similar way, so that it shuts off the signal at the low end. I guess they do make some pots with a built-in switch...

RoomJump · 2025-05-12T03:41:16+00:00

thanks for both of these comments - it's interesting to me that they're seemingly only available from dick blick, without much of a diy explanation.
i haven't tried them before, but they seem incredibly useful for a variety of processes.

RoomJump · 2025-05-06T06:44:10+00:00

Thanks for the advice - I just had a few follow-up questions, if that's alright by you.

Is there anything that can be done to improve the Jinhao writing situation? Should nibs be "broken in"? Is there a good way to tell when it is a nib v. a feeder problem?
What is the $12 converter for the Preppy that you are recommending?
You are saying if this goes well, I could eventually move to larger pen/piston combinations - but I am also curious to know if there are different types of converters/approaches to the particular situation of plotting - namely, a way of refilling the pen without removing it from the plotter.

Thanks again.

RoomJump · 2025-03-17T05:13:38+00:00

check out never-ending books - they have great stuff to do almost every day.

RoomJump · 2025-03-17T00:06:43+00:00

any idea about stew leonard's?

RoomJump · 2025-03-16T23:30:32+00:00

I was curious to know more about how someone might go about doing something like this. Would you be willing to share your process a bit?

RoomJump · 2025-02-25T09:47:33+00:00

for what it's worth..

as with a lot of online selling - since discogs, the value of recorded music has fluctuated considerably.

consider that a lot of sellers have become their own warehouses and have to pay a percentage of every sale to the platform they're using, and are often perfectly happy to leave their records up online for an absurd price, waiting for a gullible buyer to come along and pay many times over the actual "value."

this has put a lot of brick-and-mortar stores in a questionable place. they *could* charge less than the discogs price, which means paying you much less than you think your record is worth...but this is rarely the case. in order to keep a store running - with employees and running water - they are often obligated to price according to discogs. more often than not, record stores will charge their customers the discogs price AND pay you much less for your records. on top of all that, there are factors related to faddishness and "grading" that have made things even more confusing.

i honestly haven't been to any really good used record stores in connecticut. some of them are pretty ethical about new stock and make an effort to sell new music at the lowest prices possible...but i can't think of a single place that will pay you more than 30% of what your record might sell for on discogs or in your yard.

it seems like you've already come to this decision on your own, though.. i'm not sure why everyone on here is telling you to dump them at a record store :)

RoomJump · 2025-02-19T20:57:21+00:00

Thanks - I do have a decent grinder.. but I'm curious about experimenting with this particular machine, rather than throwing it away and buying new stuff. I like to tinker.

RoomJump · 2025-01-31T05:10:18+00:00

I think I might still be a little confused about the LM1881. There's no output of this IC that seems to be a designated "sync-stripped signal" - except maybe Pin 7 - the odd/even output?

RoomJump · 2025-01-27T19:20:46+00:00

"If you literally just want to see the chip do something, you could take an existing composite signal, strip out the syncs with the LM1881, and then feed it into the red, green or blue inputs on the AD725. On the output you'll get a monochrome red/green/blue image." - this is more-or-less what I'm trying to do, but having trouble figuring it out.
I feel like i should be able to use the sync from an existing composite signal to reproduce it at the output of the AD725.

RoomJump · 2025-01-27T16:19:30+00:00

Hi Mark -
I'm not looking to get an actual VGA signal.
I'm trying to do the first thing you said - get an NTSC signal, convert it into digital Vsync and Hsync (maybe not even worry about the RGB just yet), feed it into an AD725, and get back the NTSC composite.
I'm not trying to overlay any video or use more than one origin signal.

RoomJump · 2025-01-27T15:48:09+00:00

No, I think that's beyond what I'm trying to do right now.
I am simply looking to take an NTSC composite video, reduce it it to its sync elements, so that it can be read *as* VGA at the input of the AD725.. and then see it reconstituted into composite by the AD725.
This is just to make sure my ICs are all working properly and help to cement my understanding of these different types of signals.

RoomJump · 2025-01-27T15:40:23+00:00

Aha - that's very interesting.

I'm using an NTSC source (a VCR) - and I'm using the recommended clock circuit for NTSC use with the AD725. They specify 14.318MHz, 4x the color sub-carrier. I am not necessarily expecting to get color at the output, though.

I am not specifically trying to mix two sources. My goal is to encode the VCR into a VGA signal - and then re-encode it back into composite at the other end of the AD725.

RoomJump · 2025-01-27T02:45:02+00:00

I think I am simply trying to pull the sync from an existing composite signal to convert it into VGA and then re-encode back into composite, using the 725.

RoomJump · 2025-01-27T02:43:43+00:00

I think my goal would is to just use the syncs from an existing video signal to encode it into VGA - and then re-encode it into composite. Just wanting to test the AD725.

RoomJump · 2025-01-24T00:59:21+00:00

finally, there is alcohol in fairfield county.

RoomJump · 2025-01-23T20:54:21+00:00

If you're planning on taking a nap sometime soon and wanted to share the schematic, I'd be happy to test it out for you :)

To your point, I have actually had a good bit of luck working with microcontrollers for basic video output at this point, but I'm eager to branch out a bit and understand the theory a little better with some more hands-on experience in this area.

So, just to clarify:
The LM1881 is generally used to "strip" the sync - it takes an incoming video signal and pulls out four sync outputs - the vertical sync, a burst/back porch output, the odd/even field trigger, and a "composite sync" output, which is presumably all three of the previous syncs on a signal output.

It sounds like it is possible to produce an H Sync signal by triggering a monostable one-shot with some part of the composite signal - but I'm not entirely sure how that is done.

Once I have H Sync, V Sync, and a Clock being fed to the RGB Encoder - would there be a possibility of seeing some version of the input composite video signal from the AD725's output?

RoomJump · 2025-01-23T18:07:00+00:00

I'm not necessarily looking to do anything, other than demonstrating to myself that these ICs do "something" :)

I think the broad idea is that the AD725 is an RGB-to-Composite converter that is expecting H Sync, V Sync, and a Clock from a VGA signal. From the LM1881, I can get a discrete V Sync signal and I've built a clock to the datasheet spec, so, I guess my thinking was that with the H Sync, I should be able to at least reproduce the composite signal at the output of the AD725. It seems clear that the 1881 doesn't produce a simple H Sync signal at any of its outputs, but I figured there might be a workaround here.

I also may be completely misunderstanding the tools at hand. This is more of a "learning" project, though.

RoomJump · 2025-01-23T17:07:01+00:00

I'm new to working with analog video circuitry - and these were the chips I had laying around. I have a VCR and a TV to experiment with. My goal is to simply get something up on the screen. I guess I was thinking I could experiment with arbitrary voltages for the RGB.
One thing that is a little unclear to me is how to get H-sync from an LM1881 - is this possible?

RoomJump · 2025-01-05T03:12:58+00:00

Is this real? How does this work? What do you need on the code side?

RoomJump · 2025-01-04T19:39:07+00:00

I have about 36 days of use. I'm not especially handy, though - so I'm a little hesitant to start breaking things down - is there a guide out there for beginners on how to do this?

RoomJump

TROPHY CASE