During vacation I found this in a thrift store, the owner just got it in and hadn't checked it out yet so it was a gamble. Got it for 60 EUR. I have now changed belt, cleaned it up and demagnetised the head. It works great, radio has really good reception and mechanically it works perfect. Tape plays and sounds great using Dolby B or no dolby. Dolby C sounds strange, kind of chopped up not the pumping effect that I heard on other walkmans with improper calibration or tape path. I can try to upload an audio clip if there is interest. I assume the caps should be replaced as there is no Dolby calibration on this unit although I would like to have some kind of indication that this will actually help. What would you do? 1. Replace the caps and hope Dolby C works fine? 2. Keep as is and be happy about the great sound with Dolby B or no Dolby? I have several great working Dolby C walkmans already.
Yes, I think this was a great deal. A very solid unit except the plastic battery pack. I have ordered a new internal battery for it. I will leave it as is for now but I think I will do a re-cap in the future to prevent leakage and hopefully fix the Dolby C issue.
Other units I have restored from this series (JX70, 707, 929) had leaky caps. Not sure if on the 3000 they used a different brand that don't have problems, but it's something I would check. However don't expect that Dolby tracking will be improved by replacing capacitors, as the 2 are not related. Some capacitors decreasing in capacitance can cause a loss of bass (and also less volume), but won't affect the highs (which is where Dolby encoder/decoder modifies the signal). Dolby issues are caused by tape path misalignment: rollers not parallel with capstans, head tilt. In practice given the tape path is changed, head should also be lapped if there's a groove in it. Managed to get one of these units to track correctly, but after a lot of adjustments (bending) on the carriage.
Thanks @Valentin. As I understand it the 3000 is just a golden version version of 707 but I could be wrong. Looked little into finding caps and what I read is that some of the caps are difficult to find with low enough profile. If found this kit on eBay but it's quite pricey for a few caps: https://www.ebay.com/itm/187231079650 Regarding the Dolby issue it might be because of alignment although that would affect the sound of Dolby B and no Dolby. The sound is nice and crisp with no noticeable lack of high end.
The kit on ebay is way too expensive for a handful of caps. Use SMD tantalums instead, those are cheaper and can be found in 1206 package for up to 100uF and 1411 pacakge for 220uF. They're fine even as coupling capacitors, don't worry about that. Many manufacturers have used tantalums from factory. As for the Dolby tracking, C is the most sensitive. If the misalignment is really small it will affect Dolby C the most. In the past lived with the same impression: that some units sound good on Dolby OFF and B, while mistracking on C. After measuring the frequency response and seeing dips, realised the problem was there with Dolby OFF also, it was just very subtle. This can be easily checked: with the door removed take the capstans as the reference plane and check visually from one side (you can remove one of the brackets that holds the cassette) and see if head and rollers are parallel to this reference plane. Usually there's a down tilt relative to the capstans on both rollers and head.
Thanks, that is a great option. Really useful information. What is your preferred way to remove the caps? Solder iron, heat gun or cutting them off with pliers? I will have a look at the alignment, it will need to wait for some free time though. Yes, the Dolby C is sensitive and I have had mixed success so far. Dolby C players I have worked on: Achieved proper Dolby C playback 2 WM-DC-2 (Dolby level adjustment) 2 WM-D6C (Dolby level adjustment) 1 WM-DD9 (Dolby level adjustment) 1 WM-701C (Pinch rollers replacement) Not yet successful Dolby C playback 1 Aiwa HS-JX3000 - Just started investigation 1 Aiwa HS-PC202M III - likely misalignment 1 Aiwa HS-PC203 - likely misalignment 1 WM-DC2 (pointed head) - Just started investigation
My preffered way to remove caps is using soldering iron, but the corrosion needs to be cleaned a bit first otherwise it will be a bit hard to melt new solder into the old. Depends on what works for you at the end of day, all methods mentioned work fine if used correctly. Regarding Dolby tracking, from my experience most problems are caused by misalignments. Levels are a factor (as stated on other threads), but on average noticed it's less of a problem. This is the case especially on newer units which either don't have adjustments or are set pretty close to spec. 701C doesn't usually have carriage misalignment problems, most of the tape path problems being in regard to pinch rollers and/or capstans. DD9 does have misalignment problems, however due to the roller bracket design (there are 2 brackets with some room to flex), some small roller misalignments won't necccesarily cause audible problems. DC2: on DDs (here I'm reffering to center gear series) the factory azimuth it usually off because the head bridge is not exactly parallel to the mechanism chassis. To me it seems like they adjusted so head is parallel to the bridge. PC202: this unit has both misalignment and level problems. Misalignment is caused by pinch rollers and/or capstans (uneven surface). Don't have a source for new rollers at the moment. Generally speaking it's easier to obtain good results on units that are not autoreverse and have adjustable azimuth. On autoreverse units, even if the azimuth is adjustable (like PC202) it comes down to perfect tape path at the rollers, otherwise the azimuth setting will be good only for one of the 2 sides.
