{"id":12480,"date":"2015-12-01T20:17:19","date_gmt":"2015-12-01T19:17:19","guid":{"rendered":"http:\/\/www.jungsi.de\/?p=12480"},"modified":"2026-09-09T13:07:05","modified_gmt":"2026-09-09T11:07:05","slug":"epson-smd-400-wiederbelebung-atari-st","status":"publish","type":"post","link":"https:\/\/www.jungsi.de\/en\/epson-smd-400-wiederbelebung-atari-st\/","title":{"rendered":"Epson SMD-400 Wiederbelebung [Atari ST]"},"content":{"rendered":"

Some of you may have an Atari ST in your collection\u2014but have you ever stopped to consider the condition of your floppy disk drive? There is a specific drive model that Atari installed in many ST units which contains cheap electrolytic capacitors. After all these years, these can leak and destroy the motor control circuit board in the process!<\/p>\n\n\n\n

There is a remedy for this.<\/p>\n\n\n\n

feature<\/th>Value<\/th><\/tr><\/thead>
Manufacturer<\/td>Epson<\/td><\/tr>
Designation<\/td>SMD-400 (sometimes also referred to as SMD480L)<\/td><\/tr>
capacity<\/td>720 KB (Double Density)<\/td><\/tr>
Ttype<\/td>3,5\u2033<\/td><\/tr>
Used in<\/td>including internally in the Atari 1040ST<\/td><\/tr>
Spare part number (Atari)<\/td>C103043-001<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The problem: Leaking SMD electrolytic capacitors<\/h2>\n\n\n\n

This concerns the Epson SMD-400 drive. What I discovered here is something Amiga 500, 600, and 1200 owners know all too well from their own SMD electrolytic capacitors: the three small SMD capacitors had already begun to corrode the contacts. In a case like this, you should act quickly: remove the capacitors and replace them with standard leaded electrolytic capacitors. These are 10 \u00b5F capacitors\u2014five of them in total\u2014and they should be replaced as soon as possible!<\/p>\n\n\n\n

Three electrolytic capacitors are visible at the front; the fourth is located at the far rear left, and the fifth at the rear right. To access them, the entire ejection mechanism must be disassembled.<\/p>\n\n\n\n\n\n\n\n

Remove the old electrolytic capacitors and clean the contacts.<\/h2>\n\n\n\n

It is important to snap all five electrolytic capacitors off the circuit board by firmly twisting them in both directions, and then to treat the areas around the solder pads with Kontakt WL cleaner to neutralize any leaked electrolyte\u2014this is a crucial step. Afterward, use a soldering iron to remove old solder residue from the pads and clean them thoroughly using desoldering braid.<\/p>\n\n\n\n

\n\n\n\n\t\n\t
\"Epson_SMD_400_2\"<\/a><\/td>\"Epson_SMD_400_3\"<\/a><\/td>\n<\/tr>\n
Here is the partially disassembled EPSON SMD-400 floppy drive\u2014you can already see the leaking electrolytic capacitors here.<\/td>Looking at the removed electrolytic capacitor, you can already see that it has leaked and is beginning to destroy the circuit board.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/p>\n\n\n
\n
\"Epson_SMD_400_4\"<\/a><\/figure>\n<\/div>\n\n\n

Solder in new electrolytic capacitors \u2013 pay attention to polarity.<\/h2>\n\n\n\n

Each contact must then be wetted with fresh solder. Standard 10 \u00b5F electrolytic capacitors are suitable replacements; these should be installed lying flat (see image). Important: The negative side of the capacitor\u2014marked with a stripe on the casing\u2014must be connected to the negative terminal indicated on the motor control board; the unmarked side is positive. Be sure not to reverse the polarity\u2014otherwise, you\u2019ll end up with a little Chinese firecracker inside the drive \ud83d\ude42<\/p>\n\n\n

\n
\"Epson_SMD_400_5\"<\/a><\/figure>\n<\/div>\n\n\n\n\n\n\t\n\t

\"Epson_SMD_400_6\"<\/a><\/p><\/td>

\"Epson_SMD_400_7\"<\/a><\/p><\/td>\n<\/tr>\n

Here you can see the entire motor control board with the electrolytic capacitors removed. What a\u2014to use a Bavarian expression\u2014\"mess\"! All the solder pads and the surrounding contacts need to be cleaned with \"Kontakt WL\" to neutralize the electrolyte; then, all the contacts must be desoldered and re-tinned.<\/td>Here you can see the neat \"drive hack\" using brand-new, oversized 105\u00b0C low-ESR electrolytic capacitors mounted horizontally. This allows you to use standard capacitors instead of SMD types. Thanks to the capacitors' thickness, there are no clearance issues\u2014the lower drive carriage doesn't rub against them. Just make sure the polarity matches the markings on the circuit board; otherwise, a capacitor installed with the wrong polarity could burst, and we certainly don't want that! \ud83d\ude42<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n

In the picture, you can see the completed \"drive hack\" featuring new, intentionally oversized 105\u00b0C low-ESR electrolytic capacitors mounted horizontally. This eliminates the need for SMD capacitors, allowing the use of standard leaded ones. The height of the capacitors poses no issue, as the lower drive carriage does not rub against this area. The only crucial thing is ensuring the polarity matches the markings on the circuit board exactly\u2014otherwise, a capacitor installed with the wrong polarity could burst, and we certainly don't want that! \ud83d\ude42<\/p>\n\n\n\n

The height of the electrolytic capacitors fits perfectly under the carriage, so nothing rubs.<\/p>\n\n\n\n

Assembly: Be careful with the springs.<\/h2>\n\n\n\n

For this retro repair, I\u2019m assuming you have experience dismantling disk drives. The ejection mechanism springs, in particular, can drive an inexperienced person to tear their hair out \ud83d\ude42 The two lower springs for the carriage aren't a problem, but the spring for the upper carriage\u2014located at the back left\u2014can drive you absolutely mad if you don't know the right trick.<\/p>\n\n\n

\n
\"Epson_SMD_400_8\"<\/a><\/figure>\n<\/div>\n\n\n

Conclusion<\/h2>\n\n\n\n

The drive is now repaired and should function perfectly again. The contact switch for disk detection and write protection might cause some trouble in the future, though\u2014more on that soon in a separate post.<\/p>\n\n\n

\n
\"Epson_SMD_400_9\"<\/a><\/figure>\n<\/div>","protected":false},"excerpt":{"rendered":"

Der eine oder andere hat einen Atari ST in der Sammlung \u2013 doch habt ihr euch schon mal Gedanken gemacht, wie es eurem Diskettenlaufwerk geht? \u2026<\/p>","protected":false},"author":2,"featured_media":12498,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"no","_lmt_disable":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false,"_links_to":"","_links_to_target":""},"categories":[54],"tags":[668,4843,4737,4738],"class_list":["post-12480","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-atari-st","tag-atari","tag-englisch-verfuegbar","tag-hardware","tag-how-to"],"modified_by":"Jungsi","wp-worthy-pixel":{"ignored":false,"public":"538398f657014a0dbf11eda4bdde6638","server":"","url":"https:\/\/vg06.met.vgwort.de\/na\/538398f657014a0dbf11eda4bdde6638"},"wp-worthy-type":"normal","jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/www.jungsi.de\/blog\/wp-content\/uploads\/epson_smd_400_8.jpg","_links":{"self":[{"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/posts\/12480","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/comments?post=12480"}],"version-history":[{"count":2,"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/posts\/12480\/revisions"}],"predecessor-version":[{"id":48050,"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/posts\/12480\/revisions\/48050"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/media\/12498"}],"wp:attachment":[{"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/media?parent=12480"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/categories?post=12480"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jungsi.de\/en\/wp-json\/wp\/v2\/tags?post=12480"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}