Re: Tek 549 storage board anomaly
Thank you, Rajesh. Yes it seems so, as this one is #5202 (Portland facilities).
The mod has been done in 1965, as both the board picture in the available manuals and my physical board have printed "1965" in a copper/gold area.
The figure shows also the "PB" inscription, while this physical board shows "PE". A revision version?
For reference, the mentioned picture is the following:
- (BAMA manual, S/N 1408) Fig. 4-16 in page 4-11 (with a typo in the overlay label for R1185).
- (manoman.sqhill.com manual) Fig. 4-15 in page 4-10.
Both manuals are available on Kurt's site.
Regards,
Sebastian.
Rajesh VS wrote:
just for reference, I DO see R1185 in my 549, Scope Serial # - 001295.
May be the change happened in later Revs?
regds
Rajesh
. . .
toggle quoted message
Show quoted text
On Mon, Aug 6, 2018 at 8:39 PM, Sebastian Garcia <sg-listas@...>
wrote:
Hi, I know this is an old post, but same puzzle here.
Trimpot R1185 and nearby flood-gate related components (appearing in the
available PDF manuals) aren't physically present in my storage board (dated
1965).
Any clues on the storage circuits evolution of this model?
Regards,
Sebastian.
Tim Phillips <tim@...> 06/20/10 #49860
from Tim P (UK)
I am trying to cal a 549 storage 'scope ser# 701529
The manual refers to FG cathode level R1195, but
on this instrument this pot does not exist. In fact
it appears to have never existed on this storage board
(dated 1965). Both my manual and the BAMA one show it
(sectn 6-45 and the schematic) There must be another
manual with a different cal procedure. Anyone have any
insights ?
many thanks (confused) Tim P
|
Re: Tek 549 storage board anomaly
just for reference, I DO see R1185 in my 549, Scope Serial # - 001295. May be the change happened in later Revs? regds Rajesh On Mon, Aug 6, 2018 at 8:39 PM, Sebastian Garcia <sg-listas@...> wrote: Hi, I know this is an old post, but same puzzle here.
Trimpot R1185 and nearby flood-gate related components (appearing in the
available PDF manuals) aren't physically present in my storage board (dated
1965).
Any clues on the storage circuits evolution of this model?
Regards,
Sebastian.
Tim Phillips <tim@...> 06/20/10 #49860
from Tim P (UK)
I am trying to cal a 549 storage 'scope ser# 701529
The manual refers to FG cathode level R1195, but
on this instrument this pot does not exist. In fact
it appears to have never existed on this storage board
(dated 1965). Both my manual and the BAMA one show it
(sectn 6-45 and the schematic) There must be another
manual with a different cal procedure. Anyone have any
insights ?
many thanks (confused) Tim P
-- /Rajesh
|
Re: scanned: 545B and 561 Instrument Reference Books
Interesting material Kurt, so thanx for the good work.
Maybe more in the pipeline from other scopes?
¸é±ð²Ô¨¦
|
Re: Tek 549 storage board anomaly
Hi, I know this is an old post, but same puzzle here.
Trimpot R1185 and nearby flood-gate related components (appearing in the available PDF manuals) aren't physically present in my storage board (dated 1965).
Any clues on the storage circuits evolution of this model?
Regards,
Sebastian.
Tim Phillips <tim@...> 06/20/10 #49860
from Tim P (UK)
I am trying to cal a 549 storage 'scope ser# 701529
The manual refers to FG cathode level R1195, but
on this instrument this pot does not exist. In fact
it appears to have never existed on this storage board
(dated 1965). Both my manual and the BAMA one show it
(sectn 6-45 and the schematic) There must be another
manual with a different cal procedure. Anyone have any
insights ?
many thanks (confused) Tim P
|
Re: 1L20 for $95 BIN - OREGON USA
500-series plug-ins such as the 1L20 put out 0.1V/division. In contrast, 560-series mainframes expect the vertical plug-in to put out about 19.5 V/cm, due the architectural decision to have the vertical amplifier reside in the plug-ins rather than in the mainframe.
|
Re: 1L20 for $95 BIN - OREGON USA
No, and not that I'm aware of.... I'm sure some enterprising soul
could come up with an adapter tho.
The 561 takes 2xx, and 3xx series plugins. For a 561, you're looking
for a 3L5, or 3L10....
See the TekWiki for further details.
David
toggle quoted message
Show quoted text
On Mon, Aug 6, 2018 at 5:48 PM, John Griessen <john@...> wrote: Would it fit in a 561? Is there a plugin adapter for that purpose?
|
Fabio thanks for some reason I did not receive the PM responce but oh well I have it now. The only problem with your idea on this board is that none of the through hole vias is they were never soldered at all absolutely no trace of solder anywhere around all the holes. I have not investigated the A6 inter board to see if something has been done there and also with any extra wiring from somewhere else.
Jim
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Show quoted text
On August 6, 2018 at 11:58 AM Fabio Trevisan <fabio.tr3visan@...> wrote:
Hello Jim,
The pictures did arrive correctly to me and I just posted the pictures to the Tekscopes photo section:
link is here:
/g/TekScopes/album?id=65983
As I already replied in PM to you, I'll repeat it here... This rather odd missing of the through hole plating of **ONLY** the power supply rails, to me, seems like an effort of a previous owner to isolate a short-circuit in the power rails.
Given the age of those scopes, it can very well have happened before this group even existed, and before it became common knowledge that this kind of problem is often caused by a shorted tantalum capacitor, and then the scope was tossed away for - say - 20 years.
I would suggest you take advantage that the through holes are stripped out, and try to measure ohms from each of those traces to ground, everywhere that you can follow them and, if you happen to find some spot that is showing low impedance to ground... you'd have probably found the culprit.
If you can't find any of those traces shorted to ground, I would just rebuild the through-hole vias and try to apply power to the thing.
As I mentioned earlier, I don't think the presence or absence of the DM44 is too involving, in regards to the A5 trigger board and, sure enough, it has nothing to do with this mystery of the missing vias.
The only there is between the DM44 & the A5 trigger board, is the pick-off signal from the ALT TRACE SYNC PULSE, from the emitter of Q916, shown on diagram <8> of the 464 and connected through a 20K resistor, from this transistor, to a wire and then to the DM44 through pin 2 of P3201, as shown on the DM44's service manual, diagram <3> "TIME & 1/TIME <3>" and diagram <9> "464,465 & 466 INTERFACE".
The latter is the signal that tells the DM44 the end of a sweep, to allow the DM44 to switch the delay time control voltage at the end of every sweep, between the scope's own Delay time multiplier pot, and the DM44's Delta time pot (and v-v) which, ultimately is what allows the measurement of TIME and 1/TIME.
Please let us know what else did you find on this board power rails.
KRgrds,
Fabio
On Sat, Aug 4, 2018 at 09:23 PM, Jim Olson wrote:
Hi Fabio I sent the picts in an email to you PM but comcast has changed there
email to a new system so I'm not sure if you got it or not.
Jim
On August 3, 2018 at 12:23 PM Fabio Trevisan <fabio.tr3visan@...> wrote:
Hi Jim,
Feel free to send me the pictures (PM to fabio.tr3visan@...).
I will be glad to post it to the photos area of Tekscopes.io, and reply to
you with a link to the folder.
Rgrds,
Fabio
On Fri, Aug 3, 2018 at 03:07 PM, Jim Olson wrote:
Fabio I have the pictures but I'm not using any kind of photo posting
service
it's gotten to complicated and I don't post much to forums anyway so can I
send them to you and you can post them up?
Jim
On August 3, 2018 at 7:26 AM Fabio Trevisan <fabio.tr3visan@...> wrote:
Hello Jim,
I owed and restored a 464 with DM44 (now given to a friend) and I don't
think there are any other "optional" boards linked to the presence (or
absence) of the DM44.
The only optional boards that apply to the 464 / 466 are:
A. The optional DC inverter board (option 7)... That one can't co-exist
with
the DM44 (the inverter uses the same windings on the main transformer that
are
used to power the DM44).
B. The composite video Sync Separator (Option 5), which bears some
relation
to the A5 sync board and could explain some changes.
I did hear once, from someone of this group, there was two versions of
the
A5 Sync board... one that used the Tunnel Diodes, and another one which
used a
Custom Tek IC to discriminate the trigger edge.
I`m not sure, but maybe this is what the -01 means...
I've never landed my eyes, however, on a schematic of the latter, or a
later
manual that included both.
But regardless of this board versioning, It seems rather odd to me that
the
connections to the J6 are disconnected, and more so, that there is no
connection between the top and bottom side THROGUHOUT the board...
Moreover, there's nothing about the DM44 vs power to the A5 Trigger
board...
The DM44 takes its power from its own power supply and it's neither fed by
the
A5 board, nor the A5 board feeds it.
Yet, the only reason I can think of for the through hole plating is
missing
throughout the board is, either a mass murderer technician stripped them
off
by careless unsoldering, or yet, that it's a prototype board...
If it's the latter case, it could explain many things...
Maybe you can take a picture, post somewhere and link it here.
KRgrds,
Fabio
On Thu, Aug 2, 2018 at 11:40 PM, Jim Olson wrote:
I have a question about the A5 trigger generator sweep logic board
differences. I have two 466's with out the DM44 with the same trigger
board
670-3324-00 boards. I have a 464 with a DM44 with the 670-3324-01
board
and it
is vastly different from the 466 boards. All the DC voltage traces
from
J-6
are disconnected all the through holes are unsoldered so there is no
interconnection from top to bottom through out the board. There
appears to
be
no cable connection to the board from the DM44 to supply these?
The DM44 manual parts list's don't show that part number used for the
464/466
with the DM44 it shows the later 466 board and I can not find the
optional
boards listed in the service manuals listed in the DM44 one.
The installation sheets for installing the DM44's don't list different
or
optional boards used like the service manuals do?
So whats up with this bunch of missing info here!
Jim O
|
Re: 1L20 for $95 BIN - OREGON USA
Would it fit in a 561? Is there a plugin adapter for that purpose?
|
Re: 1502 internal wiring question.
On 06/08/18 21:03, Roger Evans via Groups.Io wrote: Yes, mine has exactly the same tag with a chopped off bare solid core wire 1cm or so remaining! I thought about querying this on the groups just after getting my 1502 to work but there were no problems that seemed to be linked to it. Only problem I have is that my very cheaply made NiMnH battery pack does not retain charge too well. Careful you don't overcharge the NiMH battery. There's a resistor that can be increased in order to reduce the average current. But beware that on startup it carries a significantly higher current for a second or so => have a wirewound (or similar) resistor that is tolerant to short-term overloads. Amazingly you can still get suitable NiCd cells for a reasonable price, e.g. I have one other 'loose end' wire on the 1502 which also puzzled me, what looks like it could have been an earth connection at the rear (TD end) of the strip line, but nowhere obvious that it might have linked to. My 1502 has a somewhat below spec rise time and I wondered if this could be linked to the missing earth connection. Yes; I haven't bothered to investigate mine.
|
Re: 1502 internal wiring question.
Hi Tom, Roger
Thanks for the response(s) and yes, that is exactly the tag/wire I was worried about. A bit of tinned copper has been duly applied and all is running well. I can see that will be a (probably significantly?) lower impedance than the >6 inch long drooly single crimp ground connection that it parallels!
The current drawn from the bench supply was about 240mA prior to the last failure and now sits happily at ~160mA and the 25V rail seems more stable too so I suspect that the recently failed Q6552 (feedback loop transistor) was on the way out as a result of whatever unpleasantness occurred to cause the battery negative wire insulation to go all cracked and crinkled.
Roger, I'll have a poke around the stripline tomorrow and let you know what I see in the way of grounding.
Thanks again,
Adrian
toggle quoted message
Show quoted text
On 8/6/2018 9:49 PM, Tom Gardner wrote: If you mean right by the three coloured connectors mounted on the rear of the PSU board, then there should be a 1cm bare single core wire from the chassis' tag to the 0V PCB trace on those connectors.
|
Re: 1502 internal wiring question.
On 06/08/18 18:37, Adrian wrote: Got to kick this habit! I won a 1502 TDR machine for really not a lot of $. There's little point in fighting the inevitable. I have an inordinate fondness for 1502s - except for the PSU/ battery charger :( I found another (different) dead transistor in the primary side of the LV PSU and that is now running again but although that may just have been a latent fault from whatever befell the poor thing in a previous life I want to check it a bit before firing up again. Capacitors are an obvious problem. The axial tants on the PSU are OK until they aren't - I've had a couple emit sulphuric acid (on the 25V rails, IIRC - but see an earlier message of mine. So the question: Although chassis, battery minus and 0V are electrically the same a lot of thought seems to have gone into the internal grounding/power returns of the various boards in this instrument, I presume to avoid ground loops and things, some boards don't have a '0V' wire back to the PSU but do have a chassis connection for instance and others the reverse. Given the history and crispy -ve wire evidence I want to check I am not sharing amps down returns I shouldn't and I see a large solder tag screwed to the top chassis cross-bar that has had a wire cut from it (next to a warning about the LV PSU board having 165V on it - and it has too, trust me!) but I can't see any wires floating in the breeze, does anybody who has one of these instruments know what should be connected at that
point? If you mean right by the three coloured connectors mounted on the rear of the PSU board, then there should be a 1cm bare single core wire from the chassis' tag to the 0V PCB trace on those connectors.
|
Re: 1502 internal wiring question.
Adrian,
Yes, mine has exactly the same tag with a chopped off bare solid core wire 1cm or so remaining! I thought about querying this on the groups just after getting my 1502 to work but there were no problems that seemed to be linked to it. Only problem I have is that my very cheaply made NiMnH battery pack does not retain charge too well.
I have one other 'loose end' wire on the 1502 which also puzzled me, what looks like it could have been an earth connection at the rear (TD end) of the strip line, but nowhere obvious that it might have linked to. My 1502 has a somewhat below spec rise time and I wondered if this could be linked to the missing earth connection.
Regards,
Roger
|
Hello Jim, The pictures did arrive correctly to me and I just posted the pictures to the Tekscopes photo section: link is here: /g/TekScopes/album?id=65983As I already replied in PM to you, I'll repeat it here... This rather odd missing of the through hole plating of **ONLY** the power supply rails, to me, seems like an effort of a previous owner to isolate a short-circuit in the power rails. Given the age of those scopes, it can very well have happened before this group even existed, and before it became common knowledge that this kind of problem is often caused by a shorted tantalum capacitor, and then the scope was tossed away for - say - 20 years. I would suggest you take advantage that the through holes are stripped out, and try to measure ohms from each of those traces to ground, everywhere that you can follow them and, if you happen to find some spot that is showing low impedance to ground... you'd have probably found the culprit. If you can't find any of those traces shorted to ground, I would just rebuild the through-hole vias and try to apply power to the thing. As I mentioned earlier, I don't think the presence or absence of the DM44 is too involving, in regards to the A5 trigger board and, sure enough, it has nothing to do with this mystery of the missing vias. The only there is between the DM44 & the A5 trigger board, is the pick-off signal from the ALT TRACE SYNC PULSE, from the emitter of Q916, shown on diagram <8> of the 464 and connected through a 20K resistor, from this transistor, to a wire and then to the DM44 through pin 2 of P3201, as shown on the DM44's service manual, diagram <3> "TIME & 1/TIME <3>" and diagram <9> "464,465 & 466 INTERFACE". The latter is the signal that tells the DM44 the end of a sweep, to allow the DM44 to switch the delay time control voltage at the end of every sweep, between the scope's own Delay time multiplier pot, and the DM44's Delta time pot (and v-v) which, ultimately is what allows the measurement of TIME and 1/TIME. Please let us know what else did you find on this board power rails. KRgrds, Fabio
On Sat, Aug 4, 2018 at 09:23 PM, Jim Olson wrote:
Hi Fabio I sent the picts in an email to you PM but comcast has changed there
email to a new system so I'm not sure if you got it or not.
Jim
On August 3, 2018 at 12:23 PM Fabio Trevisan <fabio.tr3visan@...> wrote:
Hi Jim,
Feel free to send me the pictures (PM to fabio.tr3visan@...).
I will be glad to post it to the photos area of Tekscopes.io, and reply to
you with a link to the folder.
Rgrds,
Fabio
On Fri, Aug 3, 2018 at 03:07 PM, Jim Olson wrote:
Fabio I have the pictures but I'm not using any kind of photo posting
service
it's gotten to complicated and I don't post much to forums anyway so can I
send them to you and you can post them up?
Jim
On August 3, 2018 at 7:26 AM Fabio Trevisan <fabio.tr3visan@...> wrote:
Hello Jim,
I owed and restored a 464 with DM44 (now given to a friend) and I don't
think there are any other "optional" boards linked to the presence (or
absence) of the DM44.
The only optional boards that apply to the 464 / 466 are:
A. The optional DC inverter board (option 7)... That one can't co-exist
with
the DM44 (the inverter uses the same windings on the main transformer that
are
used to power the DM44).
B. The composite video Sync Separator (Option 5), which bears some
relation
to the A5 sync board and could explain some changes.
I did hear once, from someone of this group, there was two versions of
the
A5 Sync board... one that used the Tunnel Diodes, and another one which
used a
Custom Tek IC to discriminate the trigger edge.
I`m not sure, but maybe this is what the -01 means...
I've never landed my eyes, however, on a schematic of the latter, or a
later
manual that included both.
But regardless of this board versioning, It seems rather odd to me that
the
connections to the J6 are disconnected, and more so, that there is no
connection between the top and bottom side THROGUHOUT the board...
Moreover, there's nothing about the DM44 vs power to the A5 Trigger
board...
The DM44 takes its power from its own power supply and it's neither fed by
the
A5 board, nor the A5 board feeds it.
Yet, the only reason I can think of for the through hole plating is
missing
throughout the board is, either a mass murderer technician stripped them
off
by careless unsoldering, or yet, that it's a prototype board...
If it's the latter case, it could explain many things...
Maybe you can take a picture, post somewhere and link it here.
KRgrds,
Fabio
On Thu, Aug 2, 2018 at 11:40 PM, Jim Olson wrote:
I have a question about the A5 trigger generator sweep logic board
differences. I have two 466's with out the DM44 with the same trigger
board
670-3324-00 boards. I have a 464 with a DM44 with the 670-3324-01
board
and it
is vastly different from the 466 boards. All the DC voltage traces
from
J-6
are disconnected all the through holes are unsoldered so there is no
interconnection from top to bottom through out the board. There
appears to
be
no cable connection to the board from the DM44 to supply these?
The DM44 manual parts list's don't show that part number used for the
464/466
with the DM44 it shows the later 466 board and I can not find the
optional
boards listed in the service manuals listed in the DM44 one.
The installation sheets for installing the DM44's don't list different
or
optional boards used like the service manuals do?
So whats up with this bunch of missing info here!
Jim O
|
1L20 for $95 BIN - OREGON USA
ITEM NUMBER 173454897871
ROLYNN
|
1502 internal wiring question.
Got to kick this habit! I won a 1502 TDR machine for really not a lot of $.
Was known non-working. The negative lead (from where the battery pack would have been if it had one) was black and crispy and 'harmonica' connector at the LV PSU end of it looked to be inspired by something Salvador Dali might have painted. Someone had been there and left behind copious amounts of gooey black tape in, presumably, an attempt to re-insulate the wire and hold the connector together.
Very few of the many power rails were where they should be volt-wise.
Worked through things and fixed all the PSU (LV & HT) issues, dead transistors in the LV PSU and a dead multiplier cap in the HT. Fired it up from a bench PSU and it seems to work pretty well, I got sensible pictures of sundry connectors and cables but after a few minutes I saw the supply current start fluctuating significantly. I was monitoring the 10V reference voltage and the +5V rail and they were both swinging around by +/- several volts and then it shut down.
I found another (different) dead transistor in the primary side of the LV PSU and that is now running again but although that may just have been a latent fault from whatever befell the poor thing in a previous life I want to check it a bit before firing up again.
So the question: Although chassis, battery minus and 0V are electrically the same a lot of thought seems to have gone into the internal grounding/power returns of the various boards in this instrument, I presume to avoid ground loops and things, some boards don't have a '0V' wire back to the PSU but do have a chassis connection for instance and others the reverse. Given the history and crispy -ve wire evidence I want to check I am not sharing amps down returns I shouldn't and I see a large solder tag screwed to the top chassis cross-bar that has had a wire cut from it (next to a warning about the LV PSU board having 165V on it - and it has too, trust me!) but I can't see any wires floating in the breeze, does anybody who has one of these instruments know what should be connected at that
point?
Many thanks,
Adrian
|
scanned: 545B and 561 Instrument Reference Books
These PDFs were by made possible by Deane Kidd and his family and friends.
|
Re: 22xx Fan supply stories
The various voltage combinations likely evolved to accommodate various fan types that were used over the years, and the actual cooling requirements. Some types may be marginal starting at reduced voltage, or too noisy at nominal voltage, and so on.
I have quite a large collection of fans pulled over the years, and have found them to have a lot of differences, even though the size and the labeled nominal voltage and current may be same. The biggest differences tend to be in startup characteristics. Some work beautifully over a wide range, while others may stall and draw excessive current if the voltage is even a little low.
When looking at a particular 2200 series model, it would be good to check the Tek and vendor part numbers and descriptions - they may have changed over the serial numbers and years, along with the details of powering them.
Also, don't forget about the rectifier forward drops in figuring the net result. Sometimes the rectifier type may be chosen to tweak the voltage too, along with the series resistance.
Again, I'd recommend always using full-wave rectification on any added fan circuits, to avoid possible PS noise issues.
Ed
|
Re: 22xx Fan supply stories
Thanks for the 2236 schematics... indeed, yet another implementation ! LOL
Tek just couldn't settle on something, seemed they were nevr happy with themselves ! ^^
It's still the same as all other implementations though : big electrolytic cap across the fan, a low value series resistor (maybe to limit in-rush current at start-up), then the only variable from one model to the other, is how much voltage they run the fan at. They always use the +/- 8.6V and +/- 5V rails.
So they can combine these rails in many ways to achieves quite a few different voltage levels, as well as using half and/or full wave rectification.. I guess the more sophisticated the scope (mostly the 2232 and 2236 then), the more power it draws, the higher the voltage Tek wanted to supply to the fan to make it move more air. Well, a fair assumption anyhow...
So depending how they combine the rails, they could get :
3.6V (8.6 - 5)
5V
8.6V
10V (x2 5V )
13.6V (5V + 8.6V) --> what the late 2236 use, then.
17.2V (x2 8.6V)
... at the least.
Talking of the 2236, I think it somehow uses the same chassis as the much more modest 2215 : on my 2215 I noticed that the front of the chassis has a cut-out where the hardware counter display would go on a 2236 (upper left of the front panel).
Vincent Trouilliez
|
Hello, The recent discussion of various 22xx fan power supplies reminded me of an odd fan supply I saw awhile back, but I couldn't remember on what 22xx model it was. Some searching turned up this odd fan circuit on the high serial number 2236 schematics which I scanned and will put up on Leo's photo album, as it might be interesting for others to see. I mentioned in the previous discussion how the 2236 had a half wave fan supply, but that only turned out to be true for the lower serial number range of the 2236's. At S/N B022267 Tektronix changed the fan power supply to an odd combination that is both full wave and half wave. I don't know much about electronics so this all seems odd to me. One leg of the fan is supplied by a half wave negative supply from pin 20 of the 8.6 volt supply with a diode,? a 2.7 Ohm resistor and a 4700 uF capacitor going to ground. The other leg is supplied directly from the full wave rectified positive voltage coming from pins 17 and 19 of the 5 volt supply to the scope. It seems like every one of these 22xx fan power supplies is a bit different, yet they still only use three components C965, CR965 and R965 in most or all(?) of them. Of course the component values vary widely from model to model. As an example on these two 2236 fan power supplies, the capacitor C965 is 270 uF on one and 4700 uF on the other, and R965 goes from 20 Ohms on one to 2.7 ohms on the other. Take a look at these two 2236 fan schematics if you are interested, they are in Leo's 2215A photo album at: /g/TekScopes/album?id=64919and please post any thoughts you have about them. tom jobe... PS The serial number at which the fan power supply changed is a guess on my part, as I used the high serial number electronic parts listings to see when C965 changed from 4700 uF to 270 uF.
|
Thanks
As you can see I a not a chemist.
I will order some 95% formic acid soon.
Glenn
toggle quoted message
Show quoted text
On 8/5/2018 3:52 PM, Sergey Kubushyn wrote: On Sun, 5 Aug 2018, Glenn Little wrote:
I use acetic acid (vinegar) to clean alkaline battery residue and baking soda in solution to clean acid battery residue. Formic acid is better than acetic -- it is more volatile than water or IPA
so whatever left after the cleaning will simply evaporates without a trace.
Don't use concentrated formic acid -- it has extremely strong odor (kinda
like acetic but many times stronger), it burns skin and will etch too much.
Dilute it with something like 5 parts of water.
As for baking soda for cleaning acid -- it is also not the best choice.
Ammonia is much better for the same reason as formic acid -- ammonium salts
are volatile unlike sodium. And excess ammonia will simply evaporate by
itself. Sodium sulfate, on the other hand, is difficult to remove completely
and it will keep etching your board. It is a very slow process but sooner or
later (couple of years) it WILL etch holes in copper traces.
---
*
*? KSI@home??? KOI8 Net? < >? The impossible we do immediately.? *
*? Las Vegas?? NV, USA?? < >? Miracles require 24-hour notice.?? *
*
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
|
Fabio Trevisan
ROLYNN PRECHTL K7DFW
Vince