r-71a warning me?

[ridgescan]

I was monitoring 11282khz usb-all of a sudden, it shot off frequency .4khz and was unstable! lsb was still fine as I tested that on 10mhz-I tried the frequency calibrator but it did no good. I shut it down for 5 minutes, turned it back on and re-adjusted the calibrator-seems to be back on line but seems to drift a bit still on usb, lsb remains fine. Could this be the internal battery giving me a warning shot?

 

[nanZor]

Here's something that might help - although circa 2000:

ANTENNIT

What comes to mind immediately is that the usb crystal is very close to the audio amp, which gets very hot. Over a decade or two, this might be causing the crystal itself to go flaky, or perhaps start to heat damage the solder connections...

I couldn't get any images in that link, but it might be helpful anyway.

 

[ridgescan]

Very valuable info-thanks! It does seem to be temp related. I let it alone for about 2 hours last night-then fired it up and it was fine on usb for the half hour I tried it. It goes off-pitch so rapidly, it would seem as though something is tweeking due to expansion. Making your case even more evident is the fact that lsb. am and cw are all normal. Thanks again hertzian

 

[jackj]

I doubt that the internal battery would only affect the USB setting. I would think that any programing error caused by a low battery would affect all modes. Another point is that a crystal's frequency doesn't change all at once due to heating, it would be a gradual drift as the crystal heats up. I would look for a bad or intermittent solder joint in the USB BFO circuit. Try taping or wiggling components in the BFO circuit.

 

[Fast1eddie]

Think mine is experiencing power supply/voltage regulation issues that occur after the set has been on for an hour or so. S Meter display bulb luminance drops off and the display becomes intermittent. Heat sensitive components in a radio this age are gonna break down eventually. Now is the time to get in there and make the mods and component improvements that Icom lacks. I have the service manual, just have to find the motivation to do so.

How's the Halli?

 

[ridgescan]

I doubt that the internal battery would only affect the USB setting. I would think that any programing error caused by a low battery would affect all modes. Another point is that a crystal's frequency doesn't change all at once due to heating, it would be a gradual drift as the crystal heats up. I would look for a bad or intermittent solder joint in the USB BFO circuit. Try taping or wiggling components in the BFO circuit.

Really good ideas to act upon Jack-thanks

Think mine is experiencing power supply/voltage regulation issues that occur after the set has been on for an hour or so. S Meter display bulb luminance drops off and the display becomes intermittent. Heat sensitive components in a radio this age are gonna break down eventually. Now is the time to get in there and make the mods and component improvements that Icom lacks. I have the service manual, just have to find the motivation to do so.

How's the Halli?

I have the sx-88 back on the kitchen table, and I am finally moving on the project. I started with photo doc and removal of three "black beauty" capacitors and one very badly charred resistor in the 1st IF stage. The resistor was so burnt it just fell in half as I snipped it out! Very difficult to read the values on it but I put it to a true radio genious on another forum and he IDd it right away. Now I have to locate new components-hopefully original types, and get them soldered back in. Hopefully these were the cause of fail. Gees I really want to see her live again.

 

[kruser]

Hey ridge,

Try and remember to post back with the remedy after you find and cure the failure of course.

There are a lot of R71's out there and they are not getting any younger so your findings may prove valuble to others down the road as the radios age even further.
I've replaced most of the lytic caps in mine, especially the ones in the power supply section. I also did a complete alignment and that made a world of difference on mine shortly after I purchased it.
I now also run it from an external power supply to minimize internal heat.
Maybe you should consider that as I know you use yours a LOT!
My R7000 runs from the same external supply. I also have an R9000 that I had on the external supply but the S-meter circuit (I think) used a voltage source before the regulator so I swapped it back to the internal supply and installed a external cooling fan. The fan keeps it very cool.
Never had another heat related failure since but I keep my fingers crossed!

 

[ridgescan]

Hey kruzer ok I will advise-although I have to admit, I get the heebiejeebies when thinking about the idea of tearing into this radio-I am a rookie and am carefully working through that hallicrafters as it is-but I too have the 71a shop manual here; I do need to buy some test equipment though. I feel that with patience and lots of care, I could pull it off

 

[nanZor]

If it were mine, I'd be tempted to at least reseat connectors and even crystals if they are in holders, just to help break any high-resistance oxidized contacts.

I'd also re-snug the circuit board screws, even if they have 20-year old colored glue on them. On some older Yaesu's, I've found that due to shrinking / flexing, after breaking the seal, many of the circuit board screws needed an additional 1/8 and in one worst case, about a 1/4 turn extra. Check regulator / heatsink bolts, and resnug if necessary. If you can, perhaps a new thin layer of modern heatsink compound might be nice.

Some of the older trimmer pots can also be oxidized, and I've broken my share of these by not taking things super-easy.

Of course the standard disclaimer applies: YMMV

 

[kruser]

If it were mine, I'd be tempted to at least reseat connectors and even crystals if they are in holders, just to help break any high-resistance oxidized contacts.

I'd also re-snug the circuit board screws, even if they have 20-year old colored glue on them. On some older Yaesu's, I've found that due to shrinking / flexing, after breaking the seal, many of the circuit board screws needed an additional 1/8 and in one worst case, about a 1/4 turn extra. Check regulator / heatsink bolts, and resnug if necessary. If you can, perhaps a new thin layer of modern heatsink compound might be nice.

Some of the older trimmer pots can also be oxidized, and I've broken my share of these by not taking things super-easy.

Of course the standard disclaimer applies: YMMV

All good advice hertzian. I should have added this into my post as I do the same with all my older radios. I also reseat IC's and wiring connectors.
IC's can work themselves out of their sockets due to thermal expansion/contraction over time. It's been a while since I've been inside my R71 but I don't recall the R71 having many (if any) socketed IC's though but the tightening of the board screws is good advice. Of course the ram board is attached via pin headers but that is not going to be his problem.
Many older radios used the frame to carry ground between the boards. I also find very lose board screws in older radios.

I do feel that ridge's problem is going to be a tad more involved but eliminating the basics is the place to start!

 

[John_S]

R-71A problems

I've seen these problems before with older (80's or so) vintage ICOM gear. Had a nice R-71A myself. If I remember correctly, there's an issue with some trimmer caps that ICOM used at the time. The best solution is to find a good repair guy and have him go through the rig. These are nice radios and worth the attention. I can heartily endorse Malcolm Technical Support in Washington. Scott is an ex ICOM tech, knows these older rigs inside out, charges fairly, and is good about getting work done in a timely fashion. He did a good job on mine.

 

[ridgescan]

Thanks for the advice John I am fortunate in that it still performs perfectly other than thes two usb drift episodes-it has been fine since. You know-I bet it was because I accidentally left the poor thing on all night last week-I never do that, but this one night, I threw the antenna switch to the r75, making the r71 go silent causing me to overlook it. It probably slowbaked the usb joints as it sat on

 

[ridgescan]

Guys quick question-my problem here is undoubtedly what hertzian called at first post-temp related. Today I had her on for an hour and bam-she kicked up 3khz during an eam-so i started blowing (LOL) into the back of the chassis and sure as s**t she slowly came back down to frequency! My question here is.. I have this cooling fan for hifi's that blows a nice gentle breeze. Do I direct the breeze INTO the back of the chassis or do I direct it the other way to "vaccuum" hot air out of the chassis? I tried positioning it at one end pointing into the rig, and felt the air exiting out the other end's venilation slats..this seems to be promising. Let me know your thoughts

 

[jackj]

Either way will work fine ridgescan. Just remember that increased air flow will mean increased dust. Might be a good idea to take the case off the radio, borrow the wife's vacuum once a year and suck the dust out.

 

[ridgescan]

Thank you Jack will keep that in mind! Much appreciate it. This ought to keep that crystal stable till I get the nerv to go in there and investigate.

 

[Fast1eddie]

Oh man, be extremely careful using any type of vacuum inside any radio! A vacuum will throw static in there and zip those IC's and other high impedance semiconductors. Use a camel hair brush and take your time!

 

[kruser]

Another option would be to do the 12 volt mod. I'm pretty sure the 12 volt connector is laying inside the radio with a jumper plug inserted into it.
You just move this plug to the rear chassis and then get yourself a decent little 12 volt regulated supply and matching connector.
This will remove a LOT of the internal heat in the R71. The internal power supply is responsible for most of the heat buildup inside. Move the power outside the chassis and your rig will run much cooler. The hardest part of the mod is mounting the plug that is laying inside to the rear of chassis. I think there was another part that is missing. I was able to use some really small screws and attach mine. Installing a different power connector is also another option. I chose to stay with the original however as that allows me to install the jumper plug back on the connector and power the radio from the internal supply again. Why Icom did not bring the 12 volt connector out the back is a mystery. The chassis is even stamped for the connector jack laying inside already! The R7000 was the same way, the power jack was taped up inside the radio. It is already wired even.

Heat is one of, if not the biggest, killer of electronics. Your symptoms show that some component is failing. The fan idea may prolong this and is not a bad idea even if you did not have any issues. I did a fan mod on my R9000. The covers are now cool to the touch. In this case, I mounted the fan so it draws air out of the rear. The R9000 has ventilation slots above the CRT on the top cover so most air is drawn in there, I was really worried that dust would get behind the frequency readout window but it never has. I do clean it out about once per year but it has not been near as bad as some of my computers get. I did use a large power resistor and slowed the fan down to the point it will still spin up from a cold condition. This keeps it running slowly so zero noise to my old ears but it is still fast enough to exhaust the internal heat.
As another pointed out, be careful if you do clean inside. A vacuum can cause radio killer static very easily. You should investigate an external supply though. I'm sure it will prolong the life of your R71 even longer.
If you do this, you should go ahead and find the bad component that you have now while inside the radio as it will likely continue to fail to the point that your fan will no longer help. I'd tend to think the failing part will be an easy fix.
Some parts are getting hard to find for these old radios so adding your cooling fan now is a good idea regardless what you decide about power options!

 

[ridgescan]

Hey kruser I will check the 12-volt thing out-I'll be looking for that 12-volt jack! This fan is great! It's doing a job on the heat-I ran the rig for 2 hours, not only was USB stable, but the case was cool to the touch the whole time. It used to get pretty hot to the touch on the sides after like 20 minutes. Now I have to ask-why didn't Icom fit a small fan to these rigs knowing the excessive heat they suffer? The fan I have on it now was conceived long before the 71a for hifi equipment cooling, and it's whisper quiet operation applies here perfectly. Now I have to locate another one for the r75 as that rig gets pretty hot-about as hot to the touch as the r71.. even with its 12-volt situation!

 

[kruser]

Hey kruser I will check the 12-volt thing out-I'll be looking for that 12-volt jack! This fan is great! It's doing a job on the heat-I ran the rig for 2 hours, not only was USB stable, but the case was cool to the touch the whole time. It used to get pretty hot to the touch on the sides after like 20 minutes. Now I have to ask-why didn't Icom fit a small fan to these rigs knowing the excessive heat they suffer? The fan I have on it now was conceived long before the 71a for hifi equipment cooling, and it's whisper quiet operation applies here perfectly. Now I have to locate another one for the r75 as that rig gets pretty hot-about as hot to the touch as the r71.. even with its 12-volt situation!

That's great that it is working Ridge! Not sure why they did not fan cool them when made. Maybe to keep cost down or maybe due to the fact that they were really well built radios and Icom used parts that would "take the heat". I'd say they did really well figuring there were made so long ago now. As parts age though, they will fail. Caps dry out, trimmers change values etc. Some of this can be prevented with forced cooling although I think that just helps the solid state parts live longer myself. I'd bet the caps and trimmers would still change or dry out regardless of cooling. Caps may be helped by cooling especially if near a heat source though.

Heer are some pics. The first pic is the fan I installed on the rear of my Icom R9000. I was wrong, I did not use a power resistor to slow it down. I bought an Antec case fan that has a 3 speed switch. I have it set on the lowest.
The 2nd is a picture of the power jack as I fitted it into the space on the rear of the R71A. The 3rd is a pic of the power jack with the bypass plug fitted. The white parts are what is laying inside the R71A. Including the part with the red wire. You plug this in when you want to use the AC power jack like you do now. If you want to use an external source, you unplug the part with the red wire and plug in a similar plug that has leads going to a external supply. The mating plugs can still be found for cheap although I don't have any links at the moment. I don't recall if the steel plate that my jack is screwed too was mounted on the rear panel or if I found that somewhere else. It may have came from the R7000. I'm thinking my R71 had just a solid blank plate in the opening for the power jack. The R9000 had the power plug fitted already. It is barely visible just left of my makeshift cooling fan.
I also have an R75 and mine does put off a little heat as well. I run mine now from a large 30 amp external supply. The same supply that runs the R71 and R7000 but not R9000. The 30 amp supply floats a large SLA battery of 12 Volt 33 Ah and that keeps my radios as well as several scanners and related preamps and stuff, running for a long time if the power goes out. I lost power this past Sunday and the battery voltage never dropped below a safe level after 6 hours.

Oh well, you will be a lot better off though now that you have a fan pulling air through your radio. It sure cannot hurt! I've never tried any of the fans sold for entertainment center equipment. Is the one you have really quiet? It looks like your fan is an 80 x 80 mm fan. Does that sound correct? I may look into some if these as they are 120 volts and would remove the fan loads from my 12 volt backup. I don't really care if I lose cooling during a power failure as they are usually short duration so I'd rather have the added runtime event hough it would not be much.

 

[ridgescan]

{Is the one you have really quiet? It looks like your fan is an 80 x 80 mm fan. Does that sound correct}?

You cannot even hear this fan running-all you do is feel the air it's pushing-it's a nice unit. The fan area is 4" in a 5" frame.
Thanks for the help kruzer