some (possibly stupid) questions regarding jenshinn/8liners.com chassis ...

[doktordee]

hi all.

sorry if any of my questions are redundant or have been covered elsewhere ... i combed through a few pages of threads after searching for "8liners" and didn't really find an answer to my questions ... in fact, reading those past threads sparked these questions since i didn't see an answer to them. so here i am. this is my first post here, so go easy on me.

here's the dirt.

i've got a couple of cabs in need of restoration, both are classics that have been converted to really awful games (for those who are curious, the cabs, in their former life before conversion to awful games, were Dragon's Lair and Defender) ...

i can't afford arcade monitors as they seem to be really expensive (roughly $200 with shipping), so the 8liners/jenshinn chassis mated with some old tv tubes look like a really economical choice for me. admittedly, i'm really quite poor, and $400+ for monitors is a bit too rich for my blood ...

with that in mind ... here are my questions.

1) in reading some of the threads on the forums, a couple of years ago people were complaining that the 8liners chassis didn't have a pincushion adjustment pot ... in seeing some of the newer threads, one person who bought a chassis for a hantarex polo said that they had a pincushion control now. is this true of the 19" chassis? in other words, did JenShinn finally add a pincushion control to all of their chassis?

2) in one of the threads i read (perhaps the same thread), people were complaining of blooming issues with the 8liners/jenshinn chassis. has this problem been resolved or do their chassis still do this? if this is still an issue, did anyone ever figure out a workaround? what causes this issue?

3) do 8liners.com offer an arcade/vga chassis similar to what the d9200 can do, or do they only offer chassis with arcade-style RGB inputs? i read an article on retroblast! (which appears as though one of the members here wrote?!?) that talked about putting an 8liners chassis on a Hantarex Polo tube, and at the end of the article an image showed a pic of the monitor with the freshly-replaced chassis hooked up to a computer, which would imply that the 8liners chassis did VGA. does 8liners make a vga/arcade chassis or did some sort of vga->rgb converter come into play that wasn't mentioned in the article?

4) if the answer to the last question posed in #3 is "yes", then how does one make such an adapter? is the answer to this question "CTFJ" (check the faq, jerky) or just simply a link to http://www.ultimarc.com/monfaq.html#monitorcable ... or is there some sort of adapter/converter that boosts the output to 5v in the process?


what's the general consensus regarding using the 8liners/jenshinn chassis? do these things seem to hold up fairly well or do they work ok for a year and then break down?

any info or help here would be fantastic.

cheers!

--doktor dee.

[Ken Layton]

$200 for an arcade monitor with shipping is cheap and reasonable. Remember arcade monitors are for commercial use and are rated as such. Plus they are built to be repaired not thrown away like tv sets.

1. I believe only the 25" model has a pincushion adjust. However, I don't know if anyone lately that has bought the 19" version to know if they finally put one on it.

2. That was on the 19" version.

3. No, only available in arcade standard resolution (CGA).

Jen Shinn is just "ok" nothing to write home about. Some people have had good life out of the chassis while others had problems out of the box.

[Pac-Fan]

1) Only the 25" models of both the JenShin and WeiYa chassis have pincushion control.  Even late 2006 built 19" JS do not have it yet.

In reality, you probably wont need it if you get a low impedence version. People have had more problem with yoke matching on the high impedence versions of both JS and WY


2) Blooming issues occured for most people on the WeiYa brand 19" chassis--not the JS. Recheck the posts here and you'll see it was WY with the issues.

All my JS ones, provided they are mated to a good tube (not significantly used) have excellent sharpness, when a WY attached to the same tube is blurrier and exhibits blooming and pusling when fed a bright signal (like more white graphics suddenly appearing on screen)


3) I believe you can get replacement chassis from both manufacturers in almost any config you want, but the resellers (8Liners aka Atlas for JS and Alva for WY) only sell the single CGA versions.


I know Ken doesn't feel the same, but I have had excellent results with numerous 19" JS low impedence chassis and with the 25" JS chassis.  I had poor results with the WeiYa 19" low impedence for picture quality and 25" with yoke compatability.  A few others have posted here with similar results.

Ken is correct--no one knows the long term durability of these replacement chassis. But I definitely will never buy another WY 19" or 25" again and will stick to JS for sharper image quality/no blooming or pulsing/wider range of yoke compatability. It's worth the extra $20 per chassis to not deal with running through more tubes or even attempting a yoke swap+reconverge.

Even with yoke compatability, be prepared to have a couple donor tubes available. Some mate perfectly others will have some geometric issues...its the luck of the draw when picking up random tubes. You'll just have better luck with JS from my experience. Also of course the donor tube is only going to be as good as it was in the TV it was in, meaning if it was loosing a color or fuzzy or overall burn in or out of convergence, it will likely experience the same issue in the chassis. That's why having a few to try is worth it.

Also, after picking up about 80 19" picture tubes over the last 5 years, I have only found 1 or 2 that were high impedence versions. Low impedence is the standard in most TV's from 1981 to 2002 that I've seen.

Finally -- with both the JS and WY chassis---stay away from their 8 pin (19") versions if possible for a couple reasons.
1) Unless you can reliably find newer tubes, most older tubes are 10 pin (type 23 pinout). Most new sets are 8 pin however.

2) The width on a standard TV yoke on 8 pin chassis generally produce a square picture (1" or more black bands on the left and right side) on the replacement chassis.  You can fix this by swapping out capacitors in the horizontal deflection circuit per Bob Roberts tips page, but definitely extra work and cost.

3) A few newer 8 pin tubes I've seen seem to have their dog ear support brackets mounted opposite from classic game monitors. That means they are almost flush with the front of the glass, rather than set back.  This makes mounting them in a classic arcade frame difficult since it leaves no room for the chassis to sit 'under' the tube. You'll have to fashion a wood frame or solid material spacers to adjust correctly.

Also, one other tip -- these replacement chassis seem to cause magnetic interference on the tube more than classic chassis. That means if you mount the chassis too close to the tube or yoke, you will experience waves/humm bars or even color shifts.

[Ken Layton]

And don't forget that Wei-ya are also sold by Billabs.

[Malenko]

you could sell me the dragons lair cab then you'd have the extra scratch to restore the defender.

[doktordee]

pac-fan:

thank you for the excellent reply. loads of info there. really appreciate it.

some more questions:

1) are there any distributors that sell a VGA version of the chassis that will mate with a tv tube? or do tv tubes just not werk for that purpose?

2) do i need to use some sort of +1v-->+5v amplifier if i am using a VGA output with this chassis? or will it work ok with the vga +1v output?

3) where can i find spare "mounting frame" to mount a tv tube in an arcade cab? am i going to have to snag them off of a dead monitor or can i just buy a frame separately?

4) is there a link to the bob roberts page you referenced (ie the deflection cap section)? i haven't checked the first donor tv i've bought just yet but in the event that it does have an 8-pin connector on the neck i want to be prepared (and hell, i just like to read)...

i'll probably come up with more questions later today -- these are the ones that spring to mind offa the top of my head...

cheers for the amazing reply.

--dee.

[doktordee]

malenko:



you probably wouldn't want this DL cab. it's covered in pigeon s**t. it also needs a lotta werk. i'm going to have to strip it, re-cover it in vinyl, and cut a new marquee frame out (the frame was cut down in its conversion to "perfect billiards"). just as an aside, it's not fer sale.

cheers.

--doktor dee

[doktordee]

ken:

thanks also for your post. all opinions and info defo help.

cheers.

--the doktor.