These are some articles about the restoring process of my unit, posted to the BA list.
Well, some of you would remember my past messages about a nice SP-600-JX and SPC-10 I found in Portugal (BTW I'm from Spain). Well, after some shipping trouble (there was a conflict with the spanish government and transport companies, which lasted two _long_ weeks), I received it yesterday... The seller did a very good (UPS prone) packaging and the receiver arrived ok.
First impressions: the SPC-10 is good inside with almost all tubes original (marked 'Hammarlund' and with very close dates, almost all from 1964), has all original knobs in very good shape but it is missing the power cord (any spare connector around?) and the front panel paint is darkened (more on this is the receiver section). Anyway, after a careful cleaning, the front panel looks old but not bad. Curiously, the front panel labels are '3-D'... I mean that they are not painted, but I think it is extruded metal (not engraved but the opposite). So I would rate the SPC-10 (not fired up yet) as 7+ cosmetically (and, hope, 8+ electrically as the seller told me both equipments worked fine).
About the SP-600-JX receiver, I was afraid of the holes in the front panel, because this was the main argument the selled had to sell it at a low price. Well, there are four holes, about 5 mm diameter and two 'half holes' (on the panel edge) of same diameter BUT all of them in the upper corners (three holes at each upper corner). Apparently, former owner did it to fix the receiver to some non-standard rack (by the way, it is a rack mount unit). Anyway, as the holes are not in the central part of the panel, I think I could live with them, so the panel could still be kept!. The receiver has all the original knobs, all in good condition except the main tunig knob, which has a mod consisting in an added lever, apparently to make tuning easier... The lever mod is well made, but perhaps an original knob could be nice (any of these around?). The meter and dials are also in very good shape, needing only some cleaning. There is some rust in some parts (mainly behind the front panel, in some metal parts) and chassis doensn't shine, but it is almost complete (only one small cover is not present, near the crystal selector). I have opened also the bottom turret cover to see a very clean rotating turret (by the way, it is normal to hear a 'crshhh' sound when you change bands?. I think it is generated by the turret contacts... ). Front panel has some scratches here and there (not big ones) but main problem is a darkened 'transparent' layer. It is present in almost all the panel but, where it is not present, painting is in very good condition!. How can I get ride of this layer?. I think that without it, paint could become a 7-8. I would rate the receiver as a 6-7 cosmetically as is now.
With the package I got a complete manual copy (good quality) for both the receiver and the SSB adapter, packaged in a bundled hard cover book. Nice job!. It is dated in 1964.
I'm curious about the exact receiver model... I know it is a SP-600-JX but I don't know if there is any suffix (as JX-17, 21, ...). Estimated manufacturing date is about 1965 (in the rear side of the panel there is a 1964 marking and the receiver has lots of 'metal square' capacitors (Cornell Dubilier) marked 0365. Is there any way to know the exact JX version?.
Summing up, I think I made a good deal and I hope to restore the receiver to an 8+ condition (at least!).
Thanks for reading this long message!. More will come as soon as I progress with the restoring and aligning process.
Hi BA gang,
Well, yesterday I started the restoration process... I removed the front panel and all parts attached to it. As I told in the first message, the painting was in very poor 'visual' condition. I mean that it had some very good parts, but the biggest surface was darkened by a thin film of 'transparent' (some time in the past) paint. I guess this was a protective coating. But now, the paint aspect was poor because of the dark (and non uniform) color. On the other hand, where this layer was missing, the painting was in good condition and with a uniform color. So, prior to sandblasting (or at least full removal of the painting), I decided to try to get ride of this ugly coating. In order to preserve the painting, I used an spanish polish product (called 'Titanlux liquid polish paste'). It took about three hours and lots of manual work (hi, my right hand still hurts me!) to get ride of all the coating (except in the parts just below the bigger knobs, where the coating is harder; but it is not visible once the knobs are in place), but the result is excellent!. And, as the polish paste I used didn't damage the paint but gave it a bright finish, now the panel is an 8+!. Only drawbacks are some small spots of peeled off paint (which of course were present at the beginning of the process), but I like to have the original paint. Then I polished also the black dial scutcheons. Now they bright as new!... This polish paste is really nice! (by the way, a 125 ml can costs about two dollar).
Once finished with the front panel, I began with the dials. A mild soap solution produced a nice looking ones.
Next step was the gear train. In the manual, I read that the gears shouldn't be lubricated... I'm not sure of the reason (any clue?). Anyway, I lubed a bit all of them, with an special good quality grease, and the movement is smoother now.
All of this ended at 23:15 local time so I went to sleep a bit ;-) ...
Today I'll begin putting back the front panel to its place and will take a look to the chassis and the tubes... Perhaps I will fire the receiver... More in the next chapter!.
Thanks for reading this boring series 8-) ... And specially to those who gave me some hints after reading part one.
Of course, any hint about restoring and / or adjusting this receiver will be welcomed!.
Hello again to all of you, firebottle fans!
The SP-600 tale continues...
Yesterday I put the front panel back to the receiver. Before doing that, I had cleaned and lubed the gears and deoxitized the potentiometers. Having looked only two days ago to the 'original' panel (with the _bad_ looking painting), I thought this was not the same receiver (add an smile here)!. My wife, who is not very fond to my BA work (perhaps I'm not the only one with this problem, hi!), told me that the receiver looked very nice and this comment has a big value for me... Only front panel parts that still needed attention were the knobs; they are all original and the only drawback is a mod consisting on an added lever in the tuning knob. I should admit that it makes the tuning smoother althought it is not pretty looking. Anyway, as the lever itself is also old and the mod is well finished, I'll let it as is by now (I tell myself that I have a customized receiver...). In order to clean the knobs, I used only water and a soft shampoo. The result was excellent; as the knobs had not scratches, they looked almost like new!. By the way, I like the knob construction; it is far better than my S-line knobs, at least in the materials. Next step was the knob installation; trouble free step. Final result: good!.
The long awaited moment was approaching... After a visual inspection and resoldering of a loose wire in a switch, I decided to fire the receiver (I'm waiting for a variac to arrive next month). The seller told me that the receiver worked and, as all his comments had proven very accurate, I had no doubt about it. I connected the antenna, then the power cord and... Nothing!!!. Dial lights didn't shine a bit!... Big trouble!... Power down immediately!... Hmmmmmmmmmm... Visual inspection again... Hi, another loosen wire in the dial lamps!. A bit of soldering added to solve that. Well, let's think a bit. I have not really checked if tubes glow (two much light and, as all have a metal enclosure and I was looking only for dial light, perhaps I missed something...). So, let's try again. Power plug... ON switch... Yahooo, dial lights!. Tubes seems to glow also. Nothing smokes. By the way, a bit of blue glow is seen in the 6V6 (I'm not sure now if it is a 6V6; I have not the schematics here). One minute waiting for sound... Nothing!. Alas, I forgot the speaker!. Well, nobody will know it, no problem, I'm alone 8-) . I hooked the output transformer (600 to 8 ohm) + S-line speaker which I use both for the R-390A and for the S-line (without transformer for the S-line, of course). Check again and... WORKS!. Some tuning after, I found one strong BC music station around 9400 KHz. The Bee-Gees are playing a nice song. Bandwidth set to 8 KHz. What a nice sound!. It is really the best I've never heard for AM!. It outperforms my R-390A (I think I have a new project: I will do the Kleronomos mod!). I had never heard an SP-600 before. It is really a pleasure!. After some deoxitizing of the BW switch, it performs almost perfectly (only in the 3KHz... sorry, Kc! position there is a bit of 'crssh'). 23:45 local time. Time to sleep... Sweet BA sleep!...
With the 'new looking' panel, the lubed gears and the deoxitized switches, my 'old' (about 1965 vintage) SP-600-JX is becoming fastly my favourite SWL receiver. Next step will be to hook the SPC-10 SSB adapter. But this is part of next chapter... stay tuned to this series!.
Hi BA gang,
Did you think that thread was over ;-) ?...
Well, yesterday I did some more cosmetic work on the SP-600. The chassis is not too clean (has a kind of dark grey oxide, forming curious patterns) but, having looked at the receiver as it came, it is in best shape that I imagined. No serious rust anywhere. I cleaned it a bit (although previous owner did a complete cleaning and there was almost no dust left). One thing I always do in any BA is to clean the tubes (without erasing the fragile markings; I let this part as is)... I _like_ doing that!. The brightness of the tubes is a must for me (I know it does nothing with performance, but I like this shinning silver / transparent surfaces). This receiver, with its 20 tubes, has only two of them without shield, so visual effect is not too evident, but anyway I did (and enjoyed) it. Another application I found for the polish paste I talked in first chapter, was the tube shields. They were full of small grey oxide spots and almost without bright... First, I toke a glass cleaner ('Cristasol', a very common product in Spain) and cleaned the shields. The result was good, but anyway I checked my trusty 'Titanlux' over the metal surfaces and... It worked!. The spots are not totally removed, but reduced in size a lot. And the shields are brighter and smoother now!.
Next step was to remove the upper turret cover... I was curious about the state of the rotating contacts, as in some message taken from the BA archives, somebody complained about broken flexible contacts. All of them were in good state, with no apparent sign of loosen strenght, and the turret was very clean. Good!. I enjoyed then two hours of SWL. This receiver really produces nice sound!. BBC news are delightful (and I practice a bit my english, hi!).
As the receiver now performs right, I plan to do a complete alignment in the future, when I get a sweep generator to align the IF stages (any one which needs a (good) home?). Anyway, I need to check some basic things, as the 'XTAL PHASING'... I'm not sure it works ok.
Some further findings about the receiver: this unih is 'black-beauties'-free :-) and, about the S/N (54609257), Tom (N5OFF) reported: 'Sounds like you have a late model. The date code is past any S.N./version data that I have. They made VLF versions in 1964, and apparently others.'... So it appears to be an interesting unit. I'll post the findings in that matter, if any.
Today I'm playing with the other element of the package, the SPC-10. After the successful cleaning of the SP-600 front panel, I have followed same procedure with the SPC-10 front panel. The 'transparent' layer was not so transparent but uniform and harder than the receiver one. So I decided only to clean (not to remove) it with 'Titanlux Liquid Polish paste' and the result has been very good: now I have a uniform colour (a bit darker than the receiver) and an smooth surface. The paste has proven good also to polish the plastic cover of the tuning meter, which was almost opaque and now is almost transparent.
Then, I have fired the converter and... Well, it works but not too fine. I've found the following:
-Noise limiter: doesn't work; when I connect it, signal vanishes completely.
-Tuning indicator: when I connect the SPC-10, it goes full to the right. Then goes slowly full to the left and remains there forever.
-Lower sideband: distorts a lot!.
-Upper sideband: low output, with a bit of distortion also.
-Both sidebands: add two previous comments and you have it.
-AVC: ???. I think this control is not working, but I'm not sure enought, due to the rest of failures.
Well, I've just opened (again; I did it two days ago to clean) the top cover of the SPC-10. By the way, this unit is very clean inside, with all tube covers in very nice condition. All the tubes are marked 'Hammarlund' and I suspect this is the main cause of failure... weak tubes here and there!. Tonight I will test oll of them with my Triplett 3444 tester. Results will be posted in next chapter. Stay tuned :-) !
Hi firebottle glow fans!
I've been working on the SPC-10 (S/N 199 for those of us interested on that information)... As I told in last message, the converter worked but not as expected... Well, this is interesting!. I like to fix tube gear, not only to clean it ;-) !. So I removed both covers, put the converter over its left side and looked inside... Hmmmmm, it is really a good manufacturing job, perhaps not Collins quality but not too far, IMHO. First than anything else, I took all the tubes and checked them with my Triplett 3444. I told previously that most of the 11 tubes in my unit were Hammarlund. Well, exactly, 8 of them are, another one (V2, 6BA6) has lost its markings (I can only guess they were yellow) and two more are Tung-Sol (V11 and V4, 6AZ8). I think that all of them except V2 are the original ones which came with the equipment (some have dates from 1964 and this is very near 1965, the estimated manufacturing date), and the other non-Hammarlund tubes are exactly same brand and date also. Anyway, only V1 (6BE6) checked a bit below its standard transconductance value and V8 (6AU6, first stage audio) if just below minimum recommended value.
Then I cleaned the rotary switchs (the SIDEBANDS and SELECTIVITY KCS switchs were very noisy) and got it working except that LSB sounded higher than USB and a bit distorted. Curiously enought, the meter and AVC now worked! (in horizontal position they didn't work). Looking into the schematics, I found a direct relation between V4 (AVC) and the meter, so I removed its shield and found that I got intermitent working of the meter when moving the tube a bit. Careful visual inspection revealed a cold solder joint in pin 5 (filament connection). I resoldered it and powered up again the converter. Shacking a bit the tube again, I got another failure!. Murphy is always hidden in the BA equipment ;-) !. Second inspection revealed a cracked wire, just touching its original position, at pin 6 of V4. Well, two failures in only one socket, not too common!. This time, the tube worked fine. So I remembered a simple test I used to do with all tube equipment; moving a bit one at a time every tube with your fingertips to look for bad contacts and dirty contacts. All of them were right, except V3 (2nd IF amp) which showed intermitent working when moved. Another cold solder joint!. This time, it was at pin 6. Well, after all of this, I have the system working a bit better, but it still suffers of the following:
-LSB: higher signal than USB and a bit distorted.
-NOISE LIMITER: doesn't work in SSB (it cancels completely the signal).
-AVC: in FAST position, the TUNING METER shows an smaller deflection than in the other positions. By the way, it works otherwise fine in this position.
-SLOT DEPTH: if this knob is intended to be linear (I mean, attenuation increasing when you go from 1 to 10), mine doesn't work that way.
Attenuation changes but not linearly and goes to a maximum about at 2. Any idea?.
Well, that's all for now!. Please, let me know if you want any further information about the SPC-10 (I have it opened now and can look inside easily). Of course, any information you think is useful to repair / adjust the converter will be welcomed!.
Thanks and best regards.