CRT question

[Trevor Wilson]

On 26/08/2019 1:57 am, Andy Burns wrote:

Trevor Wilson wrote:

Try a Rigol DS1054z. A very impressive 'scope for not too much cash

And easily hackable to add extra bandwidth and features.

**Yep. Buy the 50MHz model and convert it to 100MHz. Worst thing about
the Rigol is the probes. Truly horrible probes. The worst I've ever used.

--
Trevor Wilson
www.rageaudio.com.au

---
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[John Robertson]

On 2019/08/25 11:24 a.m., etpm@whidbey.com wrote:

On Sun, 25 Aug 2019 10:51:23 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

On Sat, 24 Aug 2019 20:04:54 -0700 (PDT), Jeff Urban
jurb6006@gmail.com> wrote:

How can you build an electronic circuit without having the schematic ?

I built quite a few Heathkit kits in the distant past that did not
require the use of a schematic. A schematic was provided by Heathkit,
but it was only useful for learning how everything works and for
troubleshooting.

I worked for a Heathkit store in the distant past for a few months.
Most of what I found were the wrong parts in the wrong holes in the
PCB. Occasionally, it was missing, extra, or substituted parts.
Amazingly, I did find one design error. Heathkits spent considerable
time and effort to avoid any assembly instructions or documentation
errors. The unspecified manufacturer of this kit might not have been
able to do as good a job. Methinks it might be worthwhile checking if
there are any addendum, corrections, mods, or changes.

I can usually find someone else's mistakes rather quickly, but have
had less luck finding my own mistakes. Maybe having someone else
check the CRT circuitry for assembly errors might be useful.

Hint: That which is obviously correct, beyond any need of checking,
is usually the problem.
I did have someone check my work and he said it should work. And it
does except for the changing focus. I am now thinking that somehow the
voltages need to be changed. The heater voltage is just below the
lowest voltage given on the spec sheet for the CRT.
Nevertheless I am going to go back and check all the solder joints
with a magnifier. And double check all the component values. The weird
thing to me is that the thing works. It just goes out of focus
gradually from one side of the display to the other.
Thanks,
Eric

Eric, have you tried contacting the kit maker? It may be a problem with
the kit that he/she wasn't aware of - defective component, etc. It happens!

'howchon at hotmail dot com' (from the home page).

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[Jeff Layman]

On 25/08/19 19:05, etpm@whidbey.com wrote:

On Sun, 25 Aug 2019 10:37:07 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

SNIP
Yeah Jeff, it really is a kit. Here's the link:
http://oscilloscopeclocknixiecrt.com/Kit.htm
I wish I had traced out the circuit before I populated the board. But
it's double sided and now really hard to see where traces go when they
hide under components.
Eric

Rather off-topic, but in one of the pictures (uncaptioned, about 2/3 to
3/4 of the way down, where the clock is on a stepped, wooden base) the
valves are nicely coloured - green on the left, purple top right, and
blue bottom right. I assume these are simply non-functional valves with
a coloured led hidden in the base. Those are pretty unusual colours for
leds; maybe a white led with a coloured filter has been used. And are
the valves non-functional? I would expect the base to get pretty hot
with the filament at that end. Not a good environment for an led.

--

Jeff

 

[Phil Allison]

Jeff Layman wrote:

--------------------

Rather off-topic, but in one of the pictures (uncaptioned, about 2/3 to
3/4 of the way down, where the clock is on a stepped, wooden base) the
valves are nicely coloured - green on the left, purple top right, and
blue bottom right. I assume these are simply non-functional valves with
a coloured led hidden in the base. Those are pretty unusual colours for
leds; maybe a white led with a coloured filter has been used. And are
the valves non-functional? I would expect the base to get pretty hot
with the filament at that end. Not a good environment for an led.

** Likely the valves are not operating and the rather bright light is coming from thin ,coloured filament bulbs - as used for xmas decorations and tree lighting.

The hole in the bottom of a 9 pin valve base is not very big.



..... Phil

 

On Monday, 26 August 2019 08:05:38 UTC+1, Jeff Layman wrote:

On 25/08/19 19:05, etpm@whidbey.com wrote:
On Sun, 25 Aug 2019 10:37:07 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

SNIP
Yeah Jeff, it really is a kit. Here's the link:
http://oscilloscopeclocknixiecrt.com/Kit.htm
I wish I had traced out the circuit before I populated the board. But
it's double sided and now really hard to see where traces go when they
hide under components.
Eric

Rather off-topic, but in one of the pictures (uncaptioned, about 2/3 to
3/4 of the way down, where the clock is on a stepped, wooden base) the
valves are nicely coloured - green on the left, purple top right, and
blue bottom right. I assume these are simply non-functional valves with
a coloured led hidden in the base. Those are pretty unusual colours for
leds; maybe a white led with a coloured filter has been used. And are
the valves non-functional? I would expect the base to get pretty hot
with the filament at that end. Not a good environment for an led.

LEDs in all sorts of oddball colours do exist, they're just a good bit more money & thus unpopular.


NT

 

On Sun, 25 Aug 2019 21:38:25 -0700, John Robertson <spam@flippers.com>
wrote:

On 2019/08/25 11:24 a.m., etpm@whidbey.com wrote:
On Sun, 25 Aug 2019 10:51:23 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

On Sat, 24 Aug 2019 20:04:54 -0700 (PDT), Jeff Urban
jurb6006@gmail.com> wrote:

How can you build an electronic circuit without having the schematic ?

I built quite a few Heathkit kits in the distant past that did not
require the use of a schematic. A schematic was provided by Heathkit,
but it was only useful for learning how everything works and for
troubleshooting.

I worked for a Heathkit store in the distant past for a few months.
Most of what I found were the wrong parts in the wrong holes in the
PCB. Occasionally, it was missing, extra, or substituted parts.
Amazingly, I did find one design error. Heathkits spent considerable
time and effort to avoid any assembly instructions or documentation
errors. The unspecified manufacturer of this kit might not have been
able to do as good a job. Methinks it might be worthwhile checking if
there are any addendum, corrections, mods, or changes.

I can usually find someone else's mistakes rather quickly, but have
had less luck finding my own mistakes. Maybe having someone else
check the CRT circuitry for assembly errors might be useful.

Hint: That which is obviously correct, beyond any need of checking,
is usually the problem.
I did have someone check my work and he said it should work. And it
does except for the changing focus. I am now thinking that somehow the
voltages need to be changed. The heater voltage is just below the
lowest voltage given on the spec sheet for the CRT.
Nevertheless I am going to go back and check all the solder joints
with a magnifier. And double check all the component values. The weird
thing to me is that the thing works. It just goes out of focus
gradually from one side of the display to the other.
Thanks,
Eric


Eric, have you tried contacting the kit maker? It may be a problem with
the kit that he/she wasn't aware of - defective component, etc. It happens!

'howchon at hotmail dot com' (from the home page).

John :-#)#

Yes, I did contact him. He has tried to help but so far nothing.
Eric