Differences between Tandberg TPT-3001 and TPT-3001A
- Thread starter BikerBoy
- Start date
Yes there are differences internally. Yes you could theoretically upgrade, but it would take replacing many of the internal boards to get there.
The touch sense circuit came in several variations, mainly during 3001 production. By the time the 3001A was produced that had stabilized. This circuit is on the main board.
The early 3001 used a pair of bipolar transistors in the limiter/detector circuit, the later ones and the 3001A used a single FET instead.
There's an extra transistor on one of the tuning system boards in the 3001A that provides power to some of the tuning system components, that wasn't present on the original 3001. Sometimes you'll see a 3001 that's been modified by tacking that transistor onto the underside of one of those boards; I think this was done by the factory or their service centers.
The two filter caps on the +25V line on the decoder board were increased from 25V to 35V parts at some point (good idea, ya think?!) , but I still see some original 3001 boards with the 25V parts on them.
Those are some things that come to mind, probably some other smaller differences that I'm overlooking.
It would be MUCH easier to swap the cabinet so you ended up with a silver 3001A, than to try and upgrade a 3001 to 3001A throughout. You'd have a heck of a time finding someone that 1) has the parts to do it, 2) has the technical skills to do it, and 3) would do it at a price that would make any sense.
John
The touch sense circuit came in several variations, mainly during 3001 production. By the time the 3001A was produced that had stabilized. This circuit is on the main board.
The early 3001 used a pair of bipolar transistors in the limiter/detector circuit, the later ones and the 3001A used a single FET instead.
There's an extra transistor on one of the tuning system boards in the 3001A that provides power to some of the tuning system components, that wasn't present on the original 3001. Sometimes you'll see a 3001 that's been modified by tacking that transistor onto the underside of one of those boards; I think this was done by the factory or their service centers.
The two filter caps on the +25V line on the decoder board were increased from 25V to 35V parts at some point (good idea, ya think?!) , but I still see some original 3001 boards with the 25V parts on them.
Those are some things that come to mind, probably some other smaller differences that I'm overlooking.
It would be MUCH easier to swap the cabinet so you ended up with a silver 3001A, than to try and upgrade a 3001 to 3001A throughout. You'd have a heck of a time finding someone that 1) has the parts to do it, 2) has the technical skills to do it, and 3) would do it at a price that would make any sense.
John
BikerBoy
New Member
John, thanks for the info. That is great advice. I am considering buying one and have seen both versions for sale. I was just trying to decide if the performance differences justify the higher prices on the 3001A. But one engineering rule never changes. Later models of most any design usually reflect improvements and corrections of mistakes that were made in the original versions. So I am certain the highest performance will be obtained by a restored 3001A. The question really is about the relative improvements versus the higher prices.
Pretty much my outlook on these as well. If you really want to follow that logic to its limit, look for a 3001A with satin gray knobs - those were final production version.
Performance isn't that different from early to late (all other things being equal, i.e. condition & alignment), but reliability is - I find 3001's are often cranky evil buggers to get working correctly, the 3001A less so. 3001's certainly take me longer to service most of the time. Some of that's probably down to age, the rest I'd attribute to continuous improvement by Tandberg over the years.
Good luck with the quest!
John
Performance isn't that different from early to late (all other things being equal, i.e. condition & alignment), but reliability is - I find 3001's are often cranky evil buggers to get working correctly, the 3001A less so. 3001's certainly take me longer to service most of the time. Some of that's probably down to age, the rest I'd attribute to continuous improvement by Tandberg over the years.
Good luck with the quest!
John
BikerBoy
New Member
Well I managed to snag a nice TPT3001A. I did a quick check and it is picking up a lot of stations but two of the preset buttons do not seem to have any engagement (probably broken) and since I don't fully understand how all the controls work, not sure what else is not working. When no antenna is connected, the signal meter actually goes negative. This unit would probably benefit from an overhaul and/or total re-alignment and check out. I will take a look inside to see if anything has been done to it before.
The standard failure mode on this is that the little rubber diaphragms inside the preset tact switches fail. Think of a little puck with conductive rubber coating that is pressed down against the gold switch contacts... the puck is suspended by a thin W (or V, can't remember) shape in the injected rubber part. It's that shape that provides the bounce-back in the switch. When that folded shape breaks along the thin V's after it gets old/fragile/pressed too many times, it lets the puck fall into the switch and the bounce-back is gone. If the puck lies across the contacts, they act as though shorted and will keep pulling the tuner into preset mode, tuned to whatever frequency was stored for that particular preset #. The display will change from F (manual mode) to the preset number as soon as you let go of the tuning knob (touching the knob disengages the servo tuning and the preset tuning).
Setting stations is a little bit of an odd sequence; you tune to the station you want, then press the preset you want first (which will immediately switch the frequency to anything it had been previously set to, but ignore that), then press and release the Program button... the display will be blinking P at that point. When it gets done storing the frequency you're currently manually tuned to, it'll pop to that preset # and the station will be heard again. the center tune meter will indicate the tuned frequency on the bottom scale of the meter. Of course, if there are switches that have shorted out internally or if it has solder joint or other internal issues, some or all of that may fail to work as expected.
Let us know what else you run into after the inspection.
John
Setting stations is a little bit of an odd sequence; you tune to the station you want, then press the preset you want first (which will immediately switch the frequency to anything it had been previously set to, but ignore that), then press and release the Program button... the display will be blinking P at that point. When it gets done storing the frequency you're currently manually tuned to, it'll pop to that preset # and the station will be heard again. the center tune meter will indicate the tuned frequency on the bottom scale of the meter. Of course, if there are switches that have shorted out internally or if it has solder joint or other internal issues, some or all of that may fail to work as expected.
Let us know what else you run into after the inspection.
John
BikerBoy
New Member
John, the bounce-back on the two leftmost preset buttons is gone--obviously the rubber puck has deteriorated. But all the presets appear to work. However, after getting a station manually tuned and perfectly centered and put into a preset, the station comes back slightly lower in frequency as shown on the tuning meter; i.e. the perfectly centered frequency is not memorized. The signal strength meter appears a bit stingy but that may be because I am not used to this unit. Next I will look inside.
BikerBoy
New Member
Here are some views inside. Memory battery fully corroded and looks like it is as old as the tuner. But for the most part the solder connections don't look bad and no exploding caps that I see. e-caps on power input look pretty old, though. I am guessing that the few orange caps I see are replacements but I am not an expert.
Attachments
The center tune meter stops being a center tune meter when you're on a preset. It displays the tuned frequency instead, look at the markings at the bottom of the scale. There actually is no way to tell from the meter whether the preset is pulling you off center tune, though you can tell by monitoring from one of the rear panel jacks or when connected to it with test gear. You CAN tell with servo tune though, try turning the Servo switch off, tune manually to a station and center the meter, then switch on Servo. If it pulls the meter off-center, one of two things is happening: either the servo adjustment is off, or the alignment points that dictate the meter indication are off and you weren't really center-tuned. You may be able to tell which by checking to see whether max signal on the lefthand meter also coincides consistently on different stations with indicated center tune on the righthand meter - not that it always is but more often than not, it will be if the alignment is correct. If you find that max signal is obtained with the center tune meter off to one side or the other, or that you hear the signal drop out/go to static quicker in one direction than the other, it's probably out of alignment.
The orange caps are low-leakage type and they're original. All of it looks original, but that battery might not be - they can leak that badly in 10 years or less, so it could have been replaced before.
On the solder joints: you haven't got it apart far enough to see the ones that cause the most trouble for the tuning circuit. Those will be on the two tuning system boards that are stacked with the solder sides facing inwards, which you will need to remove and separate in order to replace the battery and the presets. Take the whole stack out (which means also pulling the front panel forward enough to free up the preset board), then carefully separate the two. All of the header joints need examination, same for the connector to the preset board (as well as the other side that's on the preset board). Also make sure the header pins themselves are clean.
Aside from that, the problem areas for solder otherwise are the main board at the power supply, at the headers that connect the selector RF box off to the right, along the front panel switches & pots where they solder to the main board, the header points for the lighting board (there's a circuit jumper that runs across that), at the muting relay, and the headers where the plugs from the front panel plug in. Bad connections in the shielded boxes are rare.
Plan on replacing at least these five caps: the three largest in the power supply (1000uF/63V, 1000uF/50V, and 220uF/63V but I use a 220/100 for that one - there are good Nichicon caps with matching lead spacing, Mouser has all three). That is important for keeping the regulated and unregulated rails on the power supply quiet/stable. Also the two larger caps on the stereo decoder board (1000uF/35V low profile - there's a Nichicon series that fits well, think I have used UHE for that), and make sure those two haven't leaked into the PCB under the caps. If the top of the PCB is blackened after you remove the caps, and/or there is erosion on the solder side, clean all that up and in bad cases you will need to cut little trenches into the board top surfaces between the solder pads to break any carbon leakage across the caps (the board surface can become conductive if enough electrolyte has oozed into it).
Overall it looks like a typical unmolested middle production 3001A; you can tell it's not early because on the earlier ones that twisted multiharness that connects the main board to one of the tuning system boards would be a hard header board (like the lighting board); they went to this harness design later, which is more reliable - less problems with solder joints by getting rid of the hard-mounted parts & header connections.
John
The orange caps are low-leakage type and they're original. All of it looks original, but that battery might not be - they can leak that badly in 10 years or less, so it could have been replaced before.
On the solder joints: you haven't got it apart far enough to see the ones that cause the most trouble for the tuning circuit. Those will be on the two tuning system boards that are stacked with the solder sides facing inwards, which you will need to remove and separate in order to replace the battery and the presets. Take the whole stack out (which means also pulling the front panel forward enough to free up the preset board), then carefully separate the two. All of the header joints need examination, same for the connector to the preset board (as well as the other side that's on the preset board). Also make sure the header pins themselves are clean.
Aside from that, the problem areas for solder otherwise are the main board at the power supply, at the headers that connect the selector RF box off to the right, along the front panel switches & pots where they solder to the main board, the header points for the lighting board (there's a circuit jumper that runs across that), at the muting relay, and the headers where the plugs from the front panel plug in. Bad connections in the shielded boxes are rare.
Plan on replacing at least these five caps: the three largest in the power supply (1000uF/63V, 1000uF/50V, and 220uF/63V but I use a 220/100 for that one - there are good Nichicon caps with matching lead spacing, Mouser has all three). That is important for keeping the regulated and unregulated rails on the power supply quiet/stable. Also the two larger caps on the stereo decoder board (1000uF/35V low profile - there's a Nichicon series that fits well, think I have used UHE for that), and make sure those two haven't leaked into the PCB under the caps. If the top of the PCB is blackened after you remove the caps, and/or there is erosion on the solder side, clean all that up and in bad cases you will need to cut little trenches into the board top surfaces between the solder pads to break any carbon leakage across the caps (the board surface can become conductive if enough electrolyte has oozed into it).
Overall it looks like a typical unmolested middle production 3001A; you can tell it's not early because on the earlier ones that twisted multiharness that connects the main board to one of the tuning system boards would be a hard header board (like the lighting board); they went to this harness design later, which is more reliable - less problems with solder joints by getting rid of the hard-mounted parts & header connections.
John
Last edited:
I've never had to do that to get a 3001 or 3001A repaired & aligned, but ymmv. I have recapped a couple of 3011A just as an experiment on whether 1) they sound better afterwards, and 2) people will pay more for them in that condition. I'll probably do a few more, since I have the parts and tuners to do it and they did sell ok, but I wasn't convinced the sound was noticeably different.
Frankly, I would leave them alone (other than the five mentioned) if it's working - you really don't want to get very deep into component level repair on a 3001/3001A if you can help it. You can dig a hole that most techs won't want to help you out of at any price if you break something else in the process.
John
Frankly, I would leave them alone (other than the five mentioned) if it's working - you really don't want to get very deep into component level repair on a 3001/3001A if you can help it. You can dig a hole that most techs won't want to help you out of at any price if you break something else in the process.
John
R-2-R
Super Member
http://www.vintage-tuner.com/files4/tandberg.htm
Which tuner is better?.....
The 3001/3001A
or...
The 3011/3011A
Which tuner is better?.....
The 3001/3001A
or...
The 3011/3011A
Last edited:
KentTeffeteller
Gimpus Stereophilus!
These tuners should be considered as specific in terms of the condition and state of operation in terms of the specific example before you. The A series are less old (a big advantage) and have had the improvements by Tandberg incorporated. The Tandbergs do get issues with age, especially the non A models. For me, there are tuners as sensitive, which are easier repaired, sound very close to these, and less problematic with age beyond normal service issues. Please don't interpret this as me being Anti-Tandberg, because when they're in top condition and functioning correctly, I am a fanatic of them. But they're not always the most reliable with age.
3001A is the best of those, being the later evolution of that TOTL tuner design. It's fully-discrete and much more complex than the IC-based 3011/3011A, with much better resolution in terms of S/N, distortion, separation.
That said, they both sound excellent and the 3011A is a very nice tuner and less to break in it than the 3001/3001A though they all share the same tuning system with some known weak areas: failing preset switches, leaking batteries that corrode the PCB, solder failures etc.
Agree overall with Kent's assessment that popped up as I was typing this, but being relatively expert at servicing all four models at this point, the reliability has become a minor issue to me where it should be more critical to someone that has to find and pay a qualified tech to repair or align their tuner.
John
That said, they both sound excellent and the 3011A is a very nice tuner and less to break in it than the 3001/3001A though they all share the same tuning system with some known weak areas: failing preset switches, leaking batteries that corrode the PCB, solder failures etc.
Agree overall with Kent's assessment that popped up as I was typing this, but being relatively expert at servicing all four models at this point, the reliability has become a minor issue to me where it should be more critical to someone that has to find and pay a qualified tech to repair or align their tuner.
John
KentTeffeteller
Gimpus Stereophilus!
Also agree the TPT 3001A would be the best of the Tandberg tuners in terms of performance and more reliable once in good order, and they aged far better. And it's more maintainable.
liemjerry
Well-Known Member
The 3001A is top of the line among all
pari57
New Member
Basically the Tandberg units are solid products. When designed and produced, lifetime was expected to be somewhere around 20 to 30 years. Nobody would have expected them to work for 40 years or more. Without any service.!!!!
But that's what happened. My oldest is a 1978 build TPA 3002. 44 years old, fully original and fully operational. Over time complete operational units pop up. Sometimes in places where the first owner is aware of the awesome quality they bought in the 70’s or 80‘s. On the other hand, units come on the second hand market, inherited by people who had no idea at all of what they had in their hands. Remember,...with the upcoming MP3 and PC music storage period all the “old stuff” was dumped as if it was garbage. I even have seen a 3000 set 3001/3002/3003 in a car workshop, covered with 2 inches of dust and grease. (but still working). But of course, if you want to make this set new again, you’d have to put in some work in it.
As far as the 3001 (3001A) I would like to compare it with the F-15 Eagle. The basic design and product is superb. incomparable. Like the F-15 Eagle the TPT 3001 was made for 20 to 30 years of service, but at the moment still the most feared in the skies. With good care every now and then, it will run for ages and none will stand up to it.
But that's what happened. My oldest is a 1978 build TPA 3002. 44 years old, fully original and fully operational. Over time complete operational units pop up. Sometimes in places where the first owner is aware of the awesome quality they bought in the 70’s or 80‘s. On the other hand, units come on the second hand market, inherited by people who had no idea at all of what they had in their hands. Remember,...with the upcoming MP3 and PC music storage period all the “old stuff” was dumped as if it was garbage. I even have seen a 3000 set 3001/3002/3003 in a car workshop, covered with 2 inches of dust and grease. (but still working). But of course, if you want to make this set new again, you’d have to put in some work in it.
As far as the 3001 (3001A) I would like to compare it with the F-15 Eagle. The basic design and product is superb. incomparable. Like the F-15 Eagle the TPT 3001 was made for 20 to 30 years of service, but at the moment still the most feared in the skies. With good care every now and then, it will run for ages and none will stand up to it.
